24.35
Megapixels
PENTAX KAF2 (KAF2, KAF, KA)
APS-C
size sensor
Pentax K-3 Review — Hands-on Preview
by Mike Tomkins and Dave Etchells
Preview posted 10/07/2013
Since the launch of the Pentax K-7 in 2009, the company’s flagship models have been among our favorite enthusiast-grade digital SLRs. Pentax’s most recent iterations — the simultaneously-launched K-5 II and K-5 IIs — were very much evolutionary models, with only relatively minor changes from their shared predecessor. By contrast, the brand-new Pentax K-3 is revolutionary.
Not only does the K-3 feature significant changes inside and out, it also includes an industry first: on-demand low-pass filtering which lets you choose whether ultimate resolution or resistance to moiré are more important for any given shot. The attention-grabbing, mechanical alternative to an optical low-pass filter is clearly going to get all the headlines, and deservedly so, but there’s plenty else besides that makes the Pentax K-3 an exciting upgrade.
Perhaps most obviously, there’s a brand-new body that — while it retains the spirit of the design first introduced with the K-7 — makes some significant changes to the controls for the first time in several generations. The 24.3-megapixel Pentax K-3 also packs 50% more pixels into its APS-C sized image sensor, increasing linear resolution by almost a quarter. Yet thanks to a new PRIME III image processor, it simultaneously increases performance to a whopping 8.3 frames per second at full resolution, for as many as 60 JPEG or 23 raw frames. And despite the significant resolution increase, the K-3 still offers a maximum sensitivity of ISO 51,200 equivalent.
Pentax has gifted its newest APS-C flagship with a brand-new, much finer-grained metering sensor with 86,000 RGB pixels, not to mention a much more capable 27-point autofocus sensor. All but two of the K-3′s focus points are cross-types, sensitive to detail on both the horizontal and vertical axes. And at the center of the array, three points provide for autofocus with apertures as bright as f/2.8. If you prefer focusing manually, you’ll find a new focus peaking function in live view mode to be a very handy addition.
The Pentax K-3 also boasts double the shutter life of its predecessor, along with an improved image stabilization system that should better fight image blur. And on its rear panel, you’ll find both a brighter pentaprism optical viewfinder with greater magnification, and a larger, higher-resolution LCD monitor. Both storage and connectivity options have been refreshed, too. The Pentax K-3 provides dual SD card slots with support for high-speed UHS-1 cards, and supplements its high-def video output with a new USB 3.0 SuperSpeed data connection, helping you get all your images and movies off the camera in the shortest possible time.
And speaking of movie capture — long an area in which Pentax has lagged its rivals — this, too, has received a total overhaul. The Pentax K-3 now uses more efficient H.264 video compression, and provides a much more generous selection of movie frame rates. It also allows program, priority, and manual exposure control for movies. And the existing stereo microphone jack has been supplemented with a headphone jack for levels monitoring, plus a fine-grained audio levels control. You can even opt for a stereo levels display during video capture, should you wish!
Clearly, a lot has changed. The good news is that almost everything we loved about earlier Pentax flagships has been retained for the K-3. It still sports a solid magnesium-alloy body with great ergonomics, and despite an enthusiast-friendly control layout, it’s still barely any larger than the typical consumer SLR. The Pentax K-3 is also still freezeproof and fully weather-sealed. And as you’d expect, it retains enthusiast-friendly features such as a 100% pentaprism viewfinder, twin control dials, a built-in flash sync terminal, and support for an optional portrait/battery grip.
Available from November 2013, the Pentax K-3 digital SLR is priced at US$1300 body-only in the US market. A kit including the DA 18-135mm F3.5-5.6 WR zoom lens will ship for US$1,700 or thereabouts. Body-only, that’s just US$100 more than the launch price for the Pentax K-5 II, and the exact same price at which the Pentax K-5 IIs first shipped. This seems eminently reasonable, considering that the Pentax K-3 is a complete overhaul, where the earlier cameras were relatively modest updates. (To put things in perspective, the K-3 is actually priced US$300 below the launch price of the Pentax K-5, just three years ago.)
Alongside the Pentax K-3, the company is also launching several new accessories, all of which ship at the same time as the camera body in November. The Pentax D-BG5 battery grip replaces the earlier D-BG4 that was compatible with the Pentax K-7, K-5, and K-5 II / IIs models. It will be priced at around US$230 list. There will also be a new weather-sealed HD Pentax-DA 55-300mm F4-5.8ED WR lens, priced at about US$450. Finally, a Pentax-branded, Wi-Fi capable Flucard SDHC card will ship for US$100 in a 16GB capacity. Not only will this allow wireless data transfer — it will also let you control your camera remotely (including live view feed) from your PC, or from recent Android / iOS smart devices.
In the past, Pentax has also offered limited-edition silver-bodied variants of its flagship DSLRs, and it will be doing so for the Pentax K-3, as well. There’s a slight change in strategy, though. Previously, you’ve typically had to wait many months after launch to get your hands on a silver Pentax SLR. This time around, the Pentax K-3 Premium Silver Edition will ship immediately, alongside its black-bodied sibling. It will be sold in a bundle with a silver D-BG5 battery grip, and an exclusive leather strap. If you want to buy the silver Pentax K-3, you’ll need to act quickly. Just 2000 units will be offered worldwide, and with a pricetag of just US$1,600, you’ll only pay US$70 more than you would for the black version plus battery grip. At this price, it would be something of an understatement to say that we don’t expect these to hang around on store shelves.
Now that we’re done with the introductions, let’s take a closer look at the Pentax K-3!
Place your pre-order with trusted Imaging Resource affiliate Adorama now:
Pentax K-3 body — Black, body only, US$1296.95 with free shipping
Pentax K-3 18-135mm kit — Black, with 18-135mm WR kit lens, US$1646.95
Pentax K-3 Premium Silver Edition — Silver, with silver D-BG5 battery grip, US$1596.95
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Walkaround. Just like its predecessors, the Pentax K-3′s body is constructed of magnesium alloy over a steel chassis — and that’s mag-alloy on all sides, unlike some rivals. (The Nikon D7100, for example, has magnesium alloy panels top and rear, but polycarbonate plastic panels on the front, bottom, and sides.)
The K-3 is still fully dust and weather-sealed, and now sports a total of 92 different seals, up from 77 in the K-5 II. That difference is likely down to the need to seal new controls and connectivity, rather than to an increase in the already impressive water resistance. And like its predecessor, the Pentax K-3 is also freezeproof to 14°F / -10°C, while at the upper end of the range it’s possible to shoot in temperatures of 104°F / 40°C.
Although it’s still pretty compact as rugged, control-and-feature-rich enthusiast SLRs go, the Pentax K-3 has grown in size just slightly compared to its predecessors. With dimensions of 5.2 x 3.9 x 3.1 inches (131 x 100 x 77mm), it’s grown in height by around 3% (0.1 inches / 3mm), and in depth by some 5% (0.2 inches / 4mm). It’s also grown in heft, with a weight of 28.2 ounces (800g) when loaded with battery and Secure Digital card, up 5% from the 26.1 ounces (760g) of its predecessor.
Seen from the front, the Pentax K-3 looks a lot like its predecessors, the K-7, K-5, K-5 II, and K-5 IIs, but it’s actually a brand-new body. (And that’s big news, because really, there have only been very minor changes to the body design since it first debuted in 2009.)
Relatively few of the changes can be seen from the front of the camera. The handgrip has been subtly reprofiled, with a taller and deeper cutout to help give your fingers purchase, and there’s a small hump beneath the K-3 badge on the opposite side of the body. This doesn’t really affect grip much unless you’re using a pancake lens, in which case it gives a slightly more secure two-handed grip. Its main purpose, though, is to house a new headphone jack, as you’ll see in the left-side view below.
There’s also a single-hole port for the microphone, just below and to the right of the P in the Pentax logo (as seen from the rear of the camera). It’s still a mono mic, but the new position should result in slightly better reception of sound from subjects in front of the camera. Previously, it sat on the top deck.
The only other changes are very subtle. The Shake Reduction badge beneath and to the right of the lens mount is now black and gold, rather than red and silver. If you deploy the flash strobe, you’ll also find that — while its specifications are unchanged — it’s a new unit, with ever so slightly smaller surface area, and a linear Fresnel lens rather than a circular one.
On the top deck, the changes are more obvious. For one thing, you can see that the increase in body depth is largely down to a deeper thumb grip at the top right corner of the rear panel, which again helps to make for a slightly more secure and comfortable grip. The Mode dial has also been reworked, with its Movie position dropped, and the previous User position replaced by three separate user modes, U1 thru U3. (That, sadly, means that while you now have direct access, you lose two modes, since earlier models allowed five user modes to be accessed through the single User position.)
More importantly, the physical metering mode switch beneath the Mode dial is gone, replaced instead with a switch that either enables or disables the central lock button for the Mode dial. It’s a thoughtful change that caters both to fans of the existing, locking Mode dial, and those who prefer a free-spinning dial. When turned clockwise to unlock the dial, it simultaneously lowers the lock button, so you can easily feel whether or not the dial is locked. We saw something similar in the Olympus E-M1, which lets you toggle the mode dial lock each time you press the center button, so this is clearly answering a perceived need from photographers.
Another top-deck change is that the monochrome LCD info display has been revisited, with several new indications added. These include both the metering mode and AF point selection, since there are no longer physical controls that show the status of either function. The K-3 also boasts dual card slots, and the info LCD can show to which of these you’re currently writing, and in which file format.
More subtle changes include the absence of the microphone port, previously located in front of the hot shoe, and the diopter adjustment slider on top of the viewfinder. (We’ll come back to that in a moment.) Pentax has also relocated the focal plane marking to the right side of the pentaprism hump. (Previously, the marking was just to the right of the info LCD.)
The bulk of the changes, though, are to be found on the rear panel. Starting at top left, the Delete button now doubles as a Metering button when in Record mode. You simply hold it down and roll the front or rear dial to change metering modes, and the result can be confirmed either in the viewfinder, on the info LCD, or (if active) on the main LCD. The change does mean that you can’t confirm the metering mode without powering the camera on, but it also means you’re less likely to forget to check it when you glance at the info LCD. One slight quirk, though, is that you can’t change the metering mode when you’re viewing the Control Panel display. (The same is also true when you’re in the menu system, or in Playback mode.)
Moving across to the viewfinder, it looks little-changed, although its optics and internal coatings have been reworked for a slightly larger, brighter image. If you look just right of the viewfinder, though, you’ll see a new diopter adjustment dial, which replaces the previous adjustment slider that sat on top of the viewfinder. The new dial has around 20 detents that help you make small, reasonably precise adjustments, although I’m not an eyeglass-wearer, and so can’t comment on their efficacy. The adjustment range is unchanged, though, so if you were happy with the correction provided by the earlier cameras, you should be OK here too.
The change does mean that the viewfinder eyepiece frame, which is still removable, has been changed. It no longer has a cutout at its top surface for the linear slider of the earlier cameras. You can still use existing eyepieces — for example, the O-ME53 viewfinder loupe — they’ll just have a cutout for a control that isn’t there.
Just beneath the diopter adjustment dial is a new Live View / Movie Record button. This works in concert with another new control that sits near the top right corner of the LCD, the Still / Movie switch. Together, these make for a quicker and more intuitive way to switch between still capture through the viewfinder, still capture in live view mode, and movie capture. The addition of the Still / Movie switch, though, means that Pentax has also had to remove the physical AF point selection switch. We’ll come to its replacement in a moment. I’m happy to say that the Still / Movie switch is much easier to turn than the AF point selection dial was, even when shooting single-handed.
The AF button, which used to sit in the center of the AF point selection dial, has now moved to the top right corner of the camera, much where the AE Lock button used to be. I’m fine with that change, but less happy with the new location for the AE Lock button, which is very close to the corner of the camera body, and right above the hump for the rear grip. It’s not the easiest or most comfortable location to reach, but I’m sure I’ll learn to live with it.
There’s also a brand-new button at the bottom right of the corner. As I’ve already alluded to, the Pentax K-3 has dual flash card slots, and this button is used in Playback mode to switch between the two, letting you choose from which card to view images and movies. In Record mode, the same button is used to toggle the Four-way controller between its primary and secondary functions — either the functions marked on each of the four arrow buttons, or autofocus point selection. (If you’re using 27-point autofocus, the button doesn’t do anything in Record mode.)
Once again, there are also a number of more subtle changes. To accommodate a slightly larger, higher-resolution 3.2-inch LCD monitor, the controls to its right are a little tighter-spaced, especially the Info and Menu buttons. The change isn’t huge, though, and I didn’t find them any harder to identify by touch. The Four-way controller with its central OK button has also been tuned somewhat. For one thing, the Up Arrow button, which doubles as a Drive mode selector, is now also labeled as a Self-timer button. And all four Arrow buttons now have raised triangular bevels at both ends, making it easier to tell when your finger is centered on the button, and letting you press the corners of adjacent buttons together. That lets you make a diagonal selection, so that for example you can scroll diagonally in an image when using playback zoom.
The new LCD, incidentally, is a gapless type as used in the K-5 II and K-5 IIs. I don’t have access to either of those cameras at the moment, but compared to the display on my K-5, it’s a little brighter and richer. It also has noticeably better contrast and less glare. It’s no more or less prone to fingerprints than it was, though — which is to say, not terribly so.
Finally for the rear panel, Pentax has moved the IR port downwards slightly, and closer to the Four-way controller, while the card access lamp has moved upwards a bit. There’s also now a slight bevel at the rightmost edge of the LCD display, so the controls stand proud from the screen just slightly. And of course, since Pentax is now a Ricoh brand, the logo beneath the LCD monitor acknowledges this fact. (But the Pentax name still gets prime billing on the front of the camera.)
On the left hand side, there are again several changes. Key among these are a reworked Focus Mode switch, and a new AF Mode button. The focus mode switch now has only autofocus or manual focus options, and it’s easier to turn than in the past.
To switch between single-servo and continuous-servo autofocus, which was previously accomplished using the Focus Mode switch, you must now hold down the new AF Mode button while turning the front dial. If you turn the rear dial while holding down the AF Mode button, you access the various point selection options, replacing the now-absent AF Point Selection dial. Options include 27-point, 9-point, Select, and Spot.
In single-servo mode, Select allows you to choose any single point from which to focus. In continuous-servo mode, you can choose a single point to focus, and then optionally allow the camera to roam to any of eight surrounding points, any point within a 5 x 5 grid, or any point on the autofocus sensor. (And for the 3×3 or 5×5 roaming options, you can move the center point around the array.)
A couple of other changes on the left side include a new headphone jack, as alluded to earlier, plus a rearrangement of the connectivity options. The USB port — now a SuperSpeed or USB 3.0 Micro B type — sits at the top, above the HDMI and DC Inputs. The HDMI port is now a Type-D Micro connector, and the 8.3 volt DC Input is unchanged.
The rubber flap which covers all of these ports now has a bigger lip that makes it easier to pull open, but I found it quite a bit more fiddly to close, requiring me to carefully press at numerous points along its length before it would seat nicely.
The right side of the camera is little-changed externally, although the two compartment covers are now slightly longer. The reason for that change: dual SD card slots beneath the card compartment cover. The front slot is the primary, and the rear slot is the secondary. Both will accept SDHC and SDXC cards for higher capacity, and UHS-I cards for higher speed. And of course, the compartment door is still weather-sealed. Beneath sits the wired remote terminal connector door, which is unchanged from that in the earlier cameras.
And finally, the bottom of the camera looks nearly identical. There’s still a locking battery compartment door, unlocked by pulling out the metal lock hasp out with a fingernail, and then rotating it 90 degrees. You may notice a subtle change in the size of several screw holes on the Pentax K-3′s base, though. This change prevents use of the existing portrait grip — doubtless because it doesn’t quite fit the redesigned body. It’s a bit of a shame to lose compatibility with the existing grip, but in fairness, it’s lasted us through three generations since the original K-7, so I can’t gripe too much.
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Pentax K-3 Review — A Geek’s Guide to On-Demand Low-Pass Filtering
Pentax revolutionizes low-pass filtering. In a truly revolutionary move, Pentax has developed a solution for variable, on-demand low-pass (anti-aliasing) filtering in digital cameras, the first implementation being in their new K-3 DSLR. This is such an important development that we’re going to devote a little time to explaining how they do it, and why it’s so significant.
Low-pass filters, aka anti-aliasing (AA) filters are an important part of digital imaging of which most people have little understanding. Recently, there’s been a move afoot in the photo industry to eliminate them, which we at IR consider ill-advised. They’re very necessary in some situations, yet in others needlessly reduce resolution and sharpness. Clearly, what’s needed is a way to have a low-pass filter when you need it, and do away with it when you don’t. That’s exactly what Pentax has just made possible for the first time, in their new K-3 SLR.
Some background. Before getting into the details of what Pentax has done, it’d be useful to explain a bit about the role of low-pass filters in digital imaging, and just why they’re so necessary.
Ultimately, what it all comes down to is accurately reproducing the scene in front of a digital camera, without artifacts such as jaggies and false colors in the image. At the root of the issue is something called the Nyquist-Shannon Sampling Theorem (the Sampling Theorem, for short.) That’s a mouthful, and there’s a lot of complicated math behind it, but the bottom line is that you need to digitize an analog signal at twice the frequency of the highest frequency it contains.
Wait a minute: Frequency? Who said anything about frequency? Aren’t frequencies just something we worry about in audio applications?
While most of us tend to think of frequency in the context of sound, the same concept applies to images as well, in the form of spatial frequencies. To understand, think of a grid of black and white lines. The spacing between the lines corresponds to the grid’s spatial frequency. When the lines are fine and close together, that represents a higher spatial frequency; when they’re coarse and farther apart, the spatial frequency is lower. The illustration at right shows examples of low and high spatial frequencies.
The Sampling Theorem says that to accurately reproduce an image like this, we need to have twice as many pixels as the finest-pitch detail that we want to record. If we have too few, we’ll see aliasing, most obviously as moiré patterns appearing as broad, often swirling bands of tone or sometimes color, visible in the image but not present in the subject.
We’ve all probably seen moiré patterns at one time or another, perhaps on television when someone on-camera is wearing a herringbone-patterned suit or other fabric. You might also have seen color artifacts in your own digital images as well, where very fine, high-contrast details were present in the original scene.
The solution to problems like this is to insert a low-pass filter into the optical chain, before the image is digitized by the sensor. As its name suggests, a low-pass filter only lets through spatial frequencies lower than a certain value. If you set the cutoff frequency at half the pitch of the sensor pixels, you should be able to eliminate aliasing. (In actuality, you may need a lower cutoff frequency than that to avoid color artifacts, because the pitch of the color filter array on most cameras is greater than that of the underlying sensor pixels. Only the Foveon sensors used in cameras made by Sigma Corporation entirely eliminate color artifacts, because those sensors produce full red/green/blue data at every pixel location. They can still be subject to luminance artifacts, though.)
The images above show an example of what this can look like in a digital image. These are from shots taken with an Olympus E-M1, but they could as easily have come from any other camera lacking a low-pass filter, such as the Nikon D800e, Nikon D7100, Sony RX1R, or most any medium-format digital camera back. You can clearly see the swirling color patterns in the fabric of the model’s dress; take our word for it, the dress itself had no such colors in it. You can see luminance moiré patterns as well.
While clever software can do a surprising amount to eliminate artifacts like these, there will invariably be situations where they’re just unavoidable. Once they’re there, they can be nearly impossible to get rid of, depending on the subject in question.
This is at the heart of why IR believes eliminating LPFs entirely is a bad idea. You might get away with it 95% of the time, but the remaining 5% can make your life as a photographer truly miserable, with hours of Photoshop work needed to eliminate the visible effects. You might escape the consequences of not having an LPF most of the time, but when aliasing appears, you’ll sorely regret its lack.
On-demand LPF! This is where Pentax comes in, with tech that delivers LPF when you want it, and none when you don’t.
The concept isn’t entirely new. Nikon recently filed a Japanese patent on a concept for a switchable low-pass filter, although it wasn’t without some limitations. Neither is Pentax’s solution, for that matter, but in our view, it has a good bit more to offer.
Let’s take a look at how conventional LPF designs work, how Nikon’s newly-patented approach works, and then what Pentax is doing. First, conventional LPF systems.
Conventional Low-Pass Filters. As noted above, the job of a low-pass filter is to eliminate too-high spatial frequencies, by applying a very controlled blurring to the image data before it reaches the sensor’s surface. Normally, this is done by using slices of birefringent material to double the image slightly, both vertically and horizontally by a controlled amount. The illustration below (taken from our Nikon D800E review) shows how this works in practice.
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Basically, an initial low-pass filter doubles the image horizontally, a “wave plate” reorients the polarization of the light exiting the first LPF, and then a second LPF doubles the image vertically. The final result is an image that’s been blurred by a carefully controlled amount in both vertical and horizontal directions. If you blur enough, you’ll completely eliminate luminance or chroma moiré patterns and jaggies.
Of course, the catch is that, in the process of eliminating moiré, you’ve also significantly reduced image sharpness. This explains why companies have generally been weakening LPFs in recent years, and recently have begun eliminating them entirely.
Nikon’s adjustable-LPF patent. Nikon made news recently (late August, 2013) with a Japanese patent filing for an adjustable low-pass filter. Nikon’s approach inserts a liquid-crystal layer into the optical chain, between the first and second low-pass filters. When it’s turned off, the liquid-crystal rotates the plane of polarization of the light passing through it, with the result that the split image from the first LPF is recombined when it hits the second, resulting in no LPF action at all. When it’s turned on, the polarization is unchanged, so the second birefringent element splits the image further, producing a low-pass filter effect.
The diagrams above (courtesy of the Japan Patent Office) show what was just described: On the left, the liquid crystal — the layer we’ve colored green — rotates the polarization of the light by 90 degrees, so that the second birefringent element simply recombines the spit image back into a single one again. (This is how the LPF system in the Nikon D800E works; a second element undoes what the first one did. The result is that there’s no LPF function, without having changed the optical path compared to a standard D800.)
On the right, the liquid crystal is is activated so that there’s no change in polarization, and the second filter doesn’t recombine the images, but rather shifts the doubled image even more, resulting in a LPF function in the horizontal direction. (Note that we’d have to duplicate the entire system above in the vertical direction, in order to produce the combined up/down-left/right doubling of a conventional optical LPF, as in the first diagram above.)
The Nikon patent also describes using this technique to switch between heavier LPF action for video work and a lighter LPF for still capture.
It certainly seems that this could all work, and it’d be a pretty revolutionary advancement in its own right if it can be put into practice. But there’s no free lunch here; the liquid crystal layer will necessarily introduce some light loss, and to have a full, two-dimensional LPF function, you’ll need two of these setups, further reducing light transmission.
Pentax – A mechanical LPF! Now comes Pentax, with an entirely new approach to the whole question of low-pass filtering. A mechanical method!
Pentax, together with Olympus and Sony, have technology for sensor-based image stabilization. These systems shift the sensor back and forth by microscopic amounts, to compensate for camera motion, keeping the image in a stable position on the sensor’s surface. Basically, they undo blur that would happen otherwise.
But wait a minute: If the IS system can undo blur when we don’t want it, why not have it create blur when we want it?
That’s exactly how the anti-aliasing scheme in the new Pentax K-3 works. During the exposure, the anti-shake actuators oscillate the sensor assembly in either a circular or linear pattern, shifting back and forth a pixel or less in each direction. It thus does pretty much exactly what a conventional LPF system does, but without all the optical complexity — and it can be turned on or off at will. The amount of motion could even be varied to change the strength of the resulting LPF function. (As far as we know, this latter ability isn’t implemented in the K-3, but it should be pretty trivial to do so. Firmware upgrade, anyone?)
According to the briefing we received, the Pentax K-3′s mechanical anti-alias system has two different modes of operation, one in which it only moves back and forth along a single axis, andthe other in which it oscillates with a circular motion. At press time, we don’t know the reason for the single-axis mode, as it’ll only provide low-pass filtering in one direction.
This illustration shows the Pentax K-3′s sensor assembly, which “floats” inside the chassis, its precise position controlled via electromechanical actuators (the rectangular, copper-colored coils located to each side and below the sensor itself). These can move the sensor assembly with sub-pixel accuracy. Normally used for Pentax’s “SR” shake reduction feature, in the K-3, the sensor-position actuators can also produce the very slight, deliberate blurring needed to emulate a conventional optical low-pass filter.
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Whenever we hear about a radical new technology like this, the first thing we ask is “what are the tradeoffs?” In the case of Pentax’s mechanical LPF technology, our first question was what range of shutter speeds would it work over? In order to work properly, the entire sensor assembly must complete a full “orbit” of its circular motion during whatever time the shutter is open. We thus expected that there’d be some fairly low maximum shutter speed at which it could operate.
When we asked, though, we were astonished to learn that it was fully functional up to shutter speeds of 1/1000 second, and “partially functional” even higher! This means that the entire sensor assembly has to be oscillating up and down and right to left at something over a thousand times per second. (See the next section below for the results of some further analysis, though, which seems to indicate that the system is only oscillating at about 500 Hz.) While it’s only having to move a very slight amount in each direction (a pixel or less, which in this case means just 4 microns or about 15 hundred-thousandths of an inch), we were still surprised that that large a moving mass could be made to oscillate that rapidly. This is something on the order of 50x faster than needed for normal IS reduction, so perhaps Pentax has beefed up the electromagnetic actuator system for the K-3′s sensor assembly. (We also think they tuned the system to have a natural resonance at the operating frequency of the AA-simulation system.)
Another key feature of this Pentax approach to anti-aliasing is that you can vary the amount of blurring pretty arbitrarily. Again, this doesn’t appear to be implemented in the Pentax K-3, but the potential is certainly there. Imagine: A smoothly-variable low-pass filter that lets you dial in exactly the amount of filtering you need for different subjects!
Ultimately, it might even be possible to extend this system to use in video recording as well. You’d need to do something to get rid of the actuator noise, either through using an external mic, or perhaps with some clever signal-processing. Given that the AA system’s noise frequency is so well-defined (see the audio analysis in the following section), it would be pretty straightforward to knock it out of the camera’s audio without affecting the rest of the audio stream at all. (The very narrow and well-defined frequency means that a very narrow notch filter could get rid of it, with little or no impact on the rest of the audio spectrum.)
Tradeoffs? The natural question to ask at this point is what are the tradeoffs? There doesn’t seem to be much of a restriction on shutter speed, is there anything else?
Before getting to the negatives, we should note that Pentax’s approach has a big advantage over Nikon’s approach in that there’s no light loss associated with it, since there’s no added liquid-crystal layer, or even a birefringent element anywhere to be found. As we’ve pointed out, it’s also completely variable, whereas the Nikon system’s behavior is governed by fixed-size birefringent elements.
When it comes right down to it, about the only downside we see is the sound that the camera generates when the system is active; this is a mid-frequency hum, almost exactly 500 Hz by our measurements. We thought that the frequency of the oscillation might vary depending on the shutter speed in use, but our experiments with a prototype unit showed no change from 1/20 to 1/1,000 second, suggesting that the system is in fact using a natural oscillatory frequency of the sensor/actuator system. The AA system only cranks up while the shutter is open, so the hum is very short in duration, and largely masked by the shutter sound itself, although it’s more noticeable when the camera is in continuous-shooting mode. Our prototype sample seemed to disable the function at shutter speeds below 1/20 second, but that could easily change (along with other aspects we’ve reported on here) when the final firmware is released.
For those interested, here’s a link to an MP3 of the Pentax K-3′s shutter sound, with the anti-aliasing system enabled.
The image above shows the sound waveform from the K-3′s shutter when operating at 1/20 second. You can clearly see sounds associated with the initial pressing of the shutter button, the mirror opening, the AA/LPF system cranking up, the shutter opening, closing again, and finally the mirror lowering.
The waveform above shows just a portion of the cycle above, when the AA system is operating. We’ve amplified the signal a fair bit here, so you can see the frequency produced by the AA system itself more clearly.
Finally, here’s a spectrum plot of the portion of the waveform when the AA system can be heard without interference from other sounds. You can see the sharp peak from the AA system, right around 500 Hz. (502 Hz in this plot, but others with different sample lengths came out right about at 500 Hz; the exact frequency that the spike is displayed at will vary slightly depending on the length of the sequence analyzed, the type of windowing function used, etc.)
As a side note, we’re a little surprised that the system’s operating frequency was 500 Hz, vs 1 KHz or higher, given that Pentax claims full effectiveness up to shutter speeds of 1/1,000 second. It may work well enough that fast, but from what we’ve seen in the audio signature of the system, it looks to us that it should only be fully effective to 1/500 second. We’ll experiment with this a little once we receive a camera body running final firmware.
The sound artifact is doubtless why Pentax hasn’t tried to use the new AA system for video operation, where it would appear prominently in the soundtrack from in-camera mics and can be even heard fairly readily from anywhere near the camera, in a quiet environment. We have a couple of thoughts on this, though. First, the movement of the sensor assembly could be a good bit slower in video mode, which would both reduce the amplitude of the mechanical vibrations, as well as shift it to a much lower frequency, where it might be less obtrusive. The second consideration is that the sensor noise is very consistent and has a very well-defined central frequency. As noted earlier, this would make it relatively trivial to remove it from the audio track with a little signal processing. Given this, we don’t think it’ll be too long before we see this technology applied to video as well.
It’s of course possible that the system just won’t quite work as advertised, but we’ll know that pretty soon, as Pentax USA has said that they expect to receive final firmware for the camera fairly shortly after launch. (Stay tuned…)
Who can follow? While we’re sure Pentax has this new AA approach well-protected with patents, there’s always the possibility of lucrative licensing arrangements for them. Given that, it’s interesting to speculate on the extent to which this new AA technology might propagate throughout the industry. As we mentioned above, both Olympus and Sony have sensor-based image stabilization tech, so it seems that either could pretty easily adopt an approach like this, if they were able to license the concept from Pentax. Between these three companies, we could see quite a few cameras sporting this technology at some point in the future, and the capabilities of this approach wouldn’t be easily replicable by Canon or Nikon.
But what about lens-based stabilization systems? Couldn’t this same approach be applied to them, as well? Conceptually, there’s no reason why you couldn’t implement an AA system like this using lens-based IS technology. The idea would be the same; use the IS element to shift the image slightly on the focal plane during the exposure. The devil would very much be in the details, though, as the actuators for the in-lens IS elements would have to be much more robust than most are currently, to achieve sufficiently fast operation to permit reasonable shutter speeds. This could be prohibitive from a weight or power standpoint, though. The amount of motion would also have to be precisely controllable, and vary according to the size of the pixels in the camera the lens was being used with. All this makes us think it’s unlikely that we’ll see lenses incorporating this AA concept, but we’d be the last ones to definitively rule anything like that out.
Bottom line. It’s not often that we label an imaging technology “revolutionary”, but if ever one deserved to be called such, this is it. It’s a fundamentally different approach to anti-aliasing, and one that appears to have surprisingly few downsides associated with it. For the first time ever, there’s a camera on the market that lets the end-user decide when they want a low-pass filter, and when they don’t, with little apparent penalty regardless of their choice. And it was Pentax that brought it to us.
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Pentax K-3 Review — Technical Info
by Mike Tomkins
Sensor. The Pentax K-3 is now based around a 24.35-megapixel image sensor, up from the 16.3-megapixel chip used in the K-5, K-5 II, and K-5 IIs. With 50% more pixels, the new chip should yield around a 22% increase in linear resolution. Maximum image size is 6016 x 4000 pixels.
The new sensor is still a CMOS chip with Bayer RGBG filter array, but it’s fractionally smaller than the previous generation. Dimensions are 23.5 x 15.6mm, down from 23.7 x 15.7mm. Total resolution is 24.71 megapixels, well above the 16.9 megapixels of the previous-gen chip.
As in the Pentax K-5 IIs, the Pentax K-3 doesn’t include an optical low-pass filter. It does, however, add an on-demand mechanical antialiasing function. More on that in a moment. (Or read the “Geek’s Guide to On-Demand Low-Pass Filtering” by IR publisher Dave Etchells, above, for the full story.)
Processor. Also brand-new for the Pentax K-3 is a next-generation of Pentax’s image processor, now dubbed PRIME III. (That’s a contraction of “Pentax Real IMage Engine”, if you’re curious.)
The PRIME III processor replaces the PRIME II chip used in the majority of Pentax K-mount cameras since the K-7 launched way back in 2009, with only the K-30, K-50, and K-500 DSLRs and K-01 mirrorless using the intermediate PRIME M processor. The change, then, is pretty big news.
According to Pentax, the new PRIME III chip allows it to deliver improved noise reduction processing, and cleaner images. It also provides for improved performance, as we’ll see in a moment. Another nice feature is that it can handle H.264 video compression, as did the earlier PRIME M chip. That means that — unlike PRIME II cameras — Pentax is no longer limited to inefficient Motion JPEG compression in the K-3.
Sensitivity. Compared to the K-5, K-5 II, and K-5 IIs, the Pentax K-3 has a slightly narrower overall sensitivity range of ISO 100 to 51,200 equivalents, because it drops the ISO 80 position. Step sizes of 1/3, 1/2, or 1EV are available. There’s also an Auto ISO sensitivity function, whose upper limit can be manually set anywhere up to ISO 51,200 equivalent.
The good news is that the entire range is now available without needing to enable ISO expansion. This suggests that Pentax is happier with performance towards the upper end of the range than it was in the earlier cameras. (With those models, everything above ISO 12,800 was disabled by default.) That’s good news if you’re a fan of available light photography.
Another piece of good news is that there is no longer an ISO 1,600 cap when shooting in Bulb mode, as there was in earlier cameras. Bulb mode exposures now allow any ISO sensitivity to be chosen, just as in other modes.
If you’re mourning the missing ISO 80 setting, you can recapture its effect by deliberately overexposing a third stop, and then dialing back the exposure post-capture. That’s essentially what the camera was doing before, if it was configured to shoot below its native ISO. You’ll lose a little highlight detail — or latitude for pulling the exposure further — in the process, but that was already the case with the expanded ISO 80 position on earlier models anyway.
As in past cameras, you can configure the Pentax K-3 to raise sensitivity more or less readily than the default.
Performance. Pentax has increased burst performance of the K-3 beyond the already swift K-5 II and IIs. Those cameras were manufacturer-rated for seven frames per second, and in our lab testing came quite close, with a measurement of 6.7 fps. By contrast, the Pentax K-3 is manufacturer-rated for 8.3 fps, 18% faster than its predecessors. Assuming our lab testing bears this out, you can look forward to around one extra frame with the K-3 for every five you’d have shot with the earlier models.
The improved speed isn’t achieved solely thanks to the PRIME III image processor, incidentally. The processor is said to have five times greater performance, but it’s just part of the puzzle, Pentax has gifted the K-3 with a new control mechanism that regulates mirror, shutter and diaphragm motors independently, with greater speed and accuracy. It’s also designed a new mirror damping mechanism to better control mirror shock.
It’s not just burst rate that has improved, either. Pentax rates burst depth at around 60 JPEG frames, which if accurate is more than double the 28 frames we measured for the K-5 II and IIs. And while raw burst depth hasn’t shown a similar increase — Pentax is claiming 23 frames, versus the 22 frames we measured with the earlier cameras — that in itself is actually in improvement. After all, each shot now contains 50% more pixel data thanks to the increase in resolution, and there’s the increase in burst speed to take into account, as well. In fact, Pentax says that the DDR3 SDRAM buffer memory capacity in the K-3 is double that of the K-5 II, although it doesn’t state the precise amount used.
Another nice change is that there are now two reduced-speed burst shooting rates available, rather than the one offered in every flagship camera since the K-7. Not only that, but they’re both more realistic rates, as well. Instead of the not-very-useful 1.6 fps low-speed rate that was introduced with the K-5, we now have a choice of 3.0 or 4.5 fps. That should prove handy for situations where you don’t need the full 8.3 fps, but you’re still shooting faster than you’d want to by rapidly pressing the shutter button. (Although we’d still like to see the ability to manually dial in your own chosen shutter speed for reduced-rate capture.)
As you’d expect, the lower-speed burst modes have even greater burst depths. At 4.5 frames per second, Pentax claims a depth of 100 JPEG or 32 raw images. Drop the speed to 3.0 fps, and the company predicts a depth of 200 JPEG or 52 raw images.
Shake reduction. Also updated for the Pentax K-3 is the company’s three-axis Shake Reduction stabilization system, which can correct for vertical and horizontal motion, as well as for rotation around the central axis of the lens.
The system in the K-5 II and IIs could provide a four stop correction. That is to say that shooting at 1/4 second would yield a result similar to that you’d expect when shooting at 1/60th second, in terms of blur from camera shake.
Pentax Japan has yet to clarify the correction possible with the K-3′s system, but it does say that it now has a servo controller dedicated just to shake reduction, and that it has also increased the magnetic strength of the sensor shift mechanism. This, it promises, will yield “more stable, effective camera-shake compensation than ever before.”
On-demand low-pass filtering. As explained in detail by IR publisher Dave Etchells in our “Geek’s Guide to On-Demand Low-Pass Filtering” above, the Pentax K-3 is unique among all DSLRs in providing for the subtle blurring required to fight moiré, false color, and jaggies when you want it, and the maximum sharpness and detail when you don’t. With every other camera on the market, that decision was either made for you when the camera was still on the drawing board, or it was made when an assembly-line worker at the factory installed — or didn’t install — an optical low-pass filter in your particular model.
The importance of this system for your photography can’t be overstated. It places control back in your hands, letting you decide what’s most important for you on any given shot. Personally, we’d recommend shooting with the AA Filter Simulator function enabled most of the time, so that you’re not surprised by hard-to-remove moiré in a once-in-a-lifetime shot, and then selectively disabling it if you want the absolute maximum detail for a specific shot.
Because the system reaches its limits at exposures of 1/1000 second or faster, you’ll find that the strength of its effect is diminished beyond this point, regardless of your choice, something to bear in mind when choosing your exposure variables.
One thing in particular strikes us as interesting about the system: Pentax has achieved this with a Shake Reduction mechanism that was already in the camera. Yes, the SR assembly would appear to have been uprated somewhat, and that’s likely in part due to the requirements of the AA Filter Simulator function, but it’s not used solely for the function. That means it will likely have added little to the bill of materials cost, and to the final retail price of the camera.
And in the process, it means that Pentax now only needs stock one camera on store shelves, to counter two rival models — one with, and one without the low-pass filter. Half as many SKU codes means significantly less hassle in getting product on the shelf in the first place, and keeping stores stocked.
(Nor is this the only unique feature Pentax is providing with its sensor shift mechanism, as we’ll see when we come to features such as horizon correction, composition adjustment, and astral tracking. But let’s not get ahead of ourselves.)
Lens mount. It’s taken a while, but we’ve reached the first feature which hasn’t changed in the Pentax K-3 — and that’s good news. (Don’t worry, there are plenty more new features to come!)
The Pentax K-3′s KAF2 lens mount, a variant of the K-mount that has been used in all Pentax digital SLRs to date, as well as the K-01 mirrorless camera. According to Pentax, the K-mount now has the “largest offering of APS-C optimized lenses in the imaging industry”.
In all, there are 31 Pentax K-mount lens models currently on the market, ignoring variants of existing lenses such as the DA-L vs. DA (plastic vs. metal mount) and WR vs. non-WR (weather sealed vs. non-weather sealed) optics. Of these 31, all but four are DA, DA*, or DA Limited-lenses, designed for digital. Three more are D FA models, which are intended for digital SLRs, but with a 35mm full-frame image circle. That leaves 24 APS-C, digital-specific lenses.
And of course, as well as these 31 current optics, you can use older Pentax K-mount glass (some with restrictions), as well as the company’s historic 35mm screwmount and 645/67 medium format lenses with an adapter (and again, with restrictions.) You can also mount a wide selection of third-party K-mount lenses from the likes of Sigma, Tamron, and more, and optics from a healthy variety of other mounts with adapters (and limitations).
Dust removal. If you regularly change lenses — or use consumer-grade glass that sucks air in and blows it back out every time you rack the focus or zoom — you can expect dust to get inside your camera sooner or later. (Most likely, sooner.)
Pentax has retained the same DR II dust removal system used in other recent flagship models for the new K-3. It uses a piezoelectric element that vibrates at higher frequencies than a sensor shift system can, and in our experience systems like these typically do a better job of shaking free dust that’s stuck to the sensor’s protective cover glass.
To help you decide when a more detailed cleaning is needed, the Pentax K-3 also retains its predecessors’ dust alert function, which helps you to locate stubborn dust particles on the sensor for manual cleaning.
Lens correction. Also unchanged is the Pentax K-3′s lens correction functionality. This can correct for both lens distortion and lateral chromatic aberration in-camera when using DA and DFA lenses, as well as with some FA Limited lenses.
Metering. And now, for something completely different: The Pentax K-3 sports a brand-new metering sensor. Gone is the 77-segment metering sensor introduced with the K-7 back in 2009. In its place is a much finer-grained 86,000 pixel RGB CCD metering sensor.
That’s more than 1,100 pixels for every segment that was on the earlier sensor, and it should allow for much more precise metering. And since it’s an RGB chip, it can also recognize color information, allowing it to help out with subject identification. (More on that in a moment.)
Branded as the Real-Time Scene Analysis System, the new metering system also has a wider working range of -3 to 20 EV with a 50mm f/1.4 lens at ISO 100. By comparison, the earlier sensor had a range of EV 0 to 22, making it rather less sensitive in low light, although the new chip trades off a bit at the other end for its improved low-light chops.
The Pentax K-3′s metering controls are totally different to those of earlier cameras. Gone is the physical metering switch introduced with the K-7, which was fiddly to adjust, but had the advantage that you could confirm your setup without powering the camera on (and, with familiarity, by touch). In its place is a new Metering button which shares double-duty with the Delete button, at top left of the rear panel. If you hold this in and turn either dial, the metering mode is changed, and the new mode shown in the viewfinder, info LCD, and main LCD (if enabled.) And since there’s no longer a physical control for metering mode, it’s indicated at all times in the info LCD.
Although the new sensor is much finer-grained, the choice of metering modes is unchanged from earlier cameras: Multi-segment, Center-weighted, or Spot. An exposure lock function is available, accessed with the AE-L button that has been relocated to the top right corner of the camera body, above the thumb grip. You can also specify up to +/-5EV of exposure compensation, or bracket 2, 3, or 5 exposures with up to 2EV between exposures. For either compensation or bracketing, you can specify your adjustment in 1/3 or 1/2 EV steps.
Autofocus. Also brand-new is the Pentax K-3′s autofocus sensor, which is now a SAFOX 11 chip. This is the first major step forwards since the SAFOX VIII chip that was introduced a decade ago, with Pentax’s very first digital SLR, the *ist D.
Every subsequent APS-C SLR from Pentax — right up to last year’s SAFOX X — has used a variation on the SAFOX VIII layout, albeit with some important improvements in the AF sensor design, optics and algorithms. (And in a few cases on entry-level DSLRs, with the number of points having been reduced.) Never until now have we seen an overhaul like this in Pentax DSLR autofocus, though.
SAFOX 11 provides much better autofocus granularity, thanks to an increase in the number of autofocus points to 27. Of these, the 25 central points in a 5×5 array are all cross-types, sensitive to detail in both the horizontal and vertical axes. Only two points, located in the vertical center at far left and right of the array, are linear points sensitive only on one axis. (Earlier cameras, too, had mostly cross-type points — they just had a lot fewer of them.)
The centermost sensor as well as the points directly above and below it are precision points, capable of focusing with an f/2.8 aperture. That’s a feature which was introduced on the K-5 II and IIs, incidentally, although with those cameras, only the centermost point was an f/2.8 precision point. The new autofocus sensor has a working range of -3 to +18EV, unchanged from the previous SAFOX X sensor.
Just as with the metering controls, Pentax has also completely changed the controls relating to autofocus. This has most likely been done because of the added complexity of the new 27-point AF system, and while the new controls will take a little getting used to for K-7, K-5, K-5 II or K-5 IIs shooters, they’ll quickly become second nature. (And as with the metering control, the only real downside is that you can’t confirm setup without the camera being powered on.)
The Focus Mode switch sits just where it did, on the left side of the camera body behind the lens, near its base. However, it’s no longer used to choose between focus mode and servo mode. Instead, it selects solely between manual and automatic focus modes. To change the servo mode, you hold down a new AF Mode button, which sits right above the Focus Mode switch, and turn the front dial. Your choices — AF-S (single-servo), AF-C (continuous-servo), and automatic selection (AF-A) — are indicated on the camera’s displays, just as the metering modes are.
Alternatively, you can hold the AF Mode button and turn the rear dial. In this case, you’ll control the AF point selection, and here you have quite a few more choices, which depend to some extent on the servo mode setting. As well as the default 27-point auto selection, you can opt for Spot, Select, or 9-point modes. Spot is fixed at the center of the frame, but Select and 9-point modes allow you to reposition the center of the focus point cluster anywhere within the focus point array. For single-servo autofocus, Select allows only a single point to be chosen. In continuous-servo mode, it allows you to select a single point, a 3×3 array, a 5×5 array, or the entire AF array. Focus starts from the center point, but will be tracked anywhere within your selected array.
One further control is brand new, located at bottom right of the camera body. What, in the absence of a manual, I’m calling the Four-way Controller Mode button selects whether the Four-way Controller should be used to adjust the AF point location, or should abide by the markings on its buttons. Each press of this new control emits an audible beep, so you notice that you’ve changed the controller mode. And since there’s no longer a physical control for point selection, it’s now indicated in the top deck info LCD.
You might wonder why, exactly, do you need all these new autofocus points? If you’re not shooting on a tripod, you can just reframe and focus with one of the existing points, after all. It’s with tracking that the extra points are going to pay dividends, though. The more points you have, the easier it is for the camera to accurately track distance as your subject moves across the image frame. And that’s where the tie-in with the RGB metering sensor comes in, as well. Since it can now provide color information — and a whole lot finer detail — to the camera, it can be used to help track the subject’s location, and determine whether or not a given autofocus point is over the subject. In other words, we can expect quite a step forwards in tracking autofocus performance.
Hand-in-hand with this improvement, Pentax has also added a new autofocus hold setting for use in tracking, which will let you control how quickly the camera will react to a radical change in detected subject distance, such as you might get when shooting through a fence, or if somebody walked between camera and subject. You have four options, as shown in the video above: either the change will be near-instant with Hold AF Status set to off, or you can choose one of three durations (Low, Medium or High) after which the change in focus will be made.
As in the earlier cameras, you can also define whether a focus lock or a full shutter button press should be of greater importance to the Pentax K-3. In single-servo mode, you can choose focus priority to have the camera wait to trip the shutter until a focus lock is achieved, or shutter priority to take it as soon as you full press the shutter button. In continuous or AF-A modes, you can opt for focus priority, or frame rate priority (which takes another photo as soon as the shutter has recycled and there is available buffer space to do so).
Of course, you can focus manually as well. Here, there’s little new to note, although if you shoot in live view mode, there’s a new focus peaking display to help you ascertain the exact point of focus.
Pop-up flash. Although its physical design has changed subtly, with a slightly smaller surface area and a linear Fresnel lens in place of the previous circular Fresnel, the specification of the Pentax K-3′s built-in, pop-up flash is unchanged. It still has a mechanical release, and so will not scare the daylights out of you by releasing seemingly at random, as happens on some consumer cameras. It will also release with the camera powered off, though, so you’ll want to be careful that nothing could bump the button in your camera bag.
Rated at 13 meters / ISO 100, the K-3′s onboard flash offers 28mm coverage plus red-eye removal capability. The K-3 still provides X-sync at 1/180 second, offers -2 to +1EV of flash exposure compensation, and can give both first- and second-curtain flash.ÂÂ
In Wireless mode, the built-in flash can be used as a controller to multiple wireless slave flashes. The built-in flash can be set to contribute to the exposure, or to act only as a controller. The Pentax wireless flash system offers four control channels, so up to four camera/flash setups can be used in the same area without interfering with each other.
External flash. As you’d expect, there’s also a standard hot shoe on the top deck, complete with intelligent connections to support Pentax’s P-TTL flash metering system. A locking pin is also provided, to ensure your flash doesn’t detach from the camera during use.
As well as the hot shoe, the Pentax K-3 also includes a PC sync socket. It’s protected by a small, screw-in cap which isn’t attached to the camera body, so you’ll want to ensure it’s snug so as not to lose it.
Still, it’s nice to have the terminal at all — competitors such as the Canon 70D and Nikon D7100 force you to buy a hot shoe to PC terminal adapter, if you want to hook up your studio strobes.
Viewfinder. Pentax has also redesigned the viewfinder used for the Pentax K-3. Like that of earlier models dating back to the K-7, it’s pentaprism-based, and has 100% coverage.
New optics mean that it now has slightly higher 0.95x magnification, though, where the earlier design had 0.92x magnification. That might be a very small increase indeed, but it’s enough to put Pentax back to the top of the top of the APS-C viewfinder magnification charts, in a two-way tie with the Nikon D7100.
The new viewfinder is also brighter than that of the K-7, K-5, K-5 II, and K-5 IIs, thanks to a new coating on the prism with improved reflectance.
Like those which preceded it, the Pentax K-3′s new viewfinder accepts interchangeable focusing screens. The bundled screen is still a Natural-Bright-Matte III type.
Although the dioptric adjustment range of -2.5 to +1.5m-1 is unchanged, the Pentax K-3′s adjustment control is new. The earlier cameras had a linear slider control with no detents, directly above the viewfinder eyepiece. The K-3 has a rotary dial tucked in behind the right side of the viewfinder eyecup, and it has around 20 detents. While the fixed detents mean you won’t be able to adjust it *quite* as accurately, the new control is easier to adjust, and no more or less likely to be bumped.
The new design does mean that there’s a new viewfinder eyecup, as there’s no longer any need for the cutout in its top surface to provide access to the diopter adjustment slider of earlier cameras. It’s still removable, and your existing eyecups will still fit,so long as you don’t mind the vacant slot at their top.
The Pentax K-3′s LCD display is gapless, anti-glare coated, and a little larger than that of its predecessors. It also has more pixels, and a wider 3:2 aspect ratio. And yes, it has a Ricoh logo beneath it. Doubtless this will cause a little gnashing of teeth in the forums, but the Pentax badge still gets pride of place on the front of the pentaprism — and frankly, Ricoh deserves a little credit for its role in ensuring Pentax remained a viable brand.
LCD. The Pentax K-3′s rear-panel LCD monitor is also a new design. It has a slightly greater 3.2-inch diagonal, and a 3:2 aspect ratio. Together, those changes translate to around a 9% increase in surface area, and resolution has simultaneously been increased by around 13%. The total dot count is now around 1037k, up from 921k in the earlier flagships. The increase in resolution more than offsets the larger surface area, so perceived resolution is much the same as it was.
The K-3′s LCD monitor has a gapless design, as introduced on the K-5 II and IIs, and retains the anti-reflective coating of earlier models. Compared to the air-gapped design used in the K-7 and K-5, it has lower glare and better contrast. It’s also slightly brighter, richer, and saturated when compared side-by-side with the K-5. (Unfortunately, we don’t have a K-5 II or IIs on hand to compare it to.)
There is certainly one upgrade versus the K-5 II and IIs, though. The Pentax K-3′s brightness and color adjustments have been supplemented with a new saturation adjustment, letting you tweak yet another variable to your own tastes.
Info LCD. The monochrome info display on the top deck is similar to that of the earlier cameras, but adds some new information, accounting for a couple of physical control changes to the camera body. There are now indications of both metering mode and autofocus point selection, as well as of the dual flash card slots and the file types used for each.
The info LCD still has a green backlight, which illuminates when you adjust any control. If you don’t want to disturb your night vision, the backlight can be disabled.
Exposure modes. In most respects, the Pentax K-3 offers the same selection of exposure modes as did the K-5 II and IIs, as well as their predecessors. As well as Green (fully automatic), Program (with program shift), Shutter priority (Tv), Aperture priority (Av), Manual, and Bulb, there are a couple of Pentax exclusives: Sensitivity priority (Sv), and Shutter-and-Aperture priority (TAv). In these latter two modes, you can either dial in a sensitivity and let the camera select aperture and shutter speed, or dial in the aperture and shutter speed, then let the camera select the sensitivity. There’s also a Flash X-Sync mode, which locks the shutter speed at 1/180 second.
The only changes to the selection of exposure modes are that movie capture no longer merits its own position on the Mode dial, and the previous User mode has been replaced with three separate User modes (U1, U2 and U3). That’s something of a mixed blessing: It means you can now quickly access those User modes from the Mode dial, but it also means you’ve lost two user modes, since the K-5, K-5 II and K-5 IIs had five apiece. (If you’re coming from the Pentax K-7, though, you’ll actually have gained two User modes, since that model only had one.)
You can opt for various program lines when using automatic or semi-automatic exposure. As well as the default program line, you can bias the camera in favor of higher shutter speeds, a shallow or deep depth of field, or towards the MTF sweet spot of the lens.
Drive modes. Drive mode options in the Pentax K-3 include continuous (high, medium, or low), self-timer (2 or 12 second), remote control (instant, three second, or continuous), bracketing, mirror lockup, HDR, and multiple exposure. (More on these last two in the creative section below.)
As mentioned previously, burst shooting performance has been improved to 8.3 frames per second, with 4.5 fps and 3.0 fps options added in place of the earlier 1.6 fps rate. The bracketing mode allows 2, 3, or 5 shots with up to 2EV between exposures.
Shutter. The Pentax K-3′s shutter speed range is unchanged from that of the K-5 II and IIs, but the shutter mechanism itself is updated. It now has a rated lifetime of 200,000 cycles, double the 100,000 cycles of earlier models. (And you can hear that the mechanism is new, too, if you put your ear to the camera — the noise when the shutter cycles is noticeably different, although it’s just as quiet.)
Available shutter speeds range from 1/8000 to 30 seconds in 1/3 or 1/2 EV steps, plus bulb.
White balance. In most respects, white balance with the Pentax K-3 is similar to preceding models, but one feature is new. There’s now a Multi Auto WB mode, which aims to neutralize color casts from multiple different light sources in the same scene. It’s an adoption from new parent Ricoh, whose cameras have had the feature for a while now under another name: Multi-P Auto.
As well as Automatic and Manual modes, the Pentax K-3 provides ten white balance presets (Daylight, Shade, Cloudy, Daylight Color Fluorescent, Daylight White Fluorescent, Cool White Fluorescent, Warm White Fluorescent, Tungsten, Flash, and Color Temperature Enhancement). This last option is used to retain and enhance the lighting tone – for example, to enhance a sunset.
White balance can also be measured from a neutral target, or a specific color temperature can be dialed in manually, using either Kelvin or Mired values. Three custom white balance values of each type can be stored in-camera. And finally, you can adjust white balance within a +/- 7-step range on both amber-blue and green-magenta axes.
Creative. To say that the Pentax K-3 has a healthy selection of creative options would be an understatement. We’ve already briefly mentioned a couple: HDR mode and multiple-exposure shooting.
HDR mode captures multiple images, then microaligns them in camera and blends them to create a single image with greater dynamic range. You have a choice of automatic blending, or one of three effect strengths. These range from fairly natural to a bolder, crunchier feel. (And since the images are microaligned, the mode can be used handheld.) We believe from the press materials that the mode now allows you to output a raw image, although we’ve yet to try this ourselves.
Multiple exposure mode is similar to that in earlier cameras, but with two changes. It still allows you to merge multiple images (either starting from an existing raw file, or by shooting a new image), and you can still save your result as a raw image as well. However, there are now three methods of merging images. In addition to the existing additive and average modes, there’s now a bright mode which takes the brightest pixel at any given location in the source images, and uses that in the final image. You can also now merge up to 2000 frames, rather than the previous limit of nine frames. (Although in the past you could circumvent that limit by saving as raw, and then reimporting the previous raw file as a new starting point.)
There’s also a time-lapse function, which allows shots at 2-second to 24-hour intervals. You can now capture a lot more shots in an interval series, however. Instead of the 999 shot limit of the K-5, K-5 II, and K-5 IIs, the Pentax K-3 will shoot as many as 2000 shots in a series.
There is now one more custom image effect in the Pentax K-3, and four new pre-capture digital filter effects have replaced existing ones which have been retired. The new custom image effect is called Radiant, and the new pre-capture digital filters are Shading, Invert Color, Unicolor Bold, and Bold Monochrome. These were all seen previously in the Pentax Q and Q7 mirrorless cameras, and they replace the earlier Soft, Starburst, Fish-eye, and Custom filters from earlier K-series flagships.
Copyright tagging. Like the flagship models which precede it, the Pentax K-3 can optionally embed copyright data into its raw and JPEG image files. You can enter both a photographer and copyright holder name from the camera body, and the headers of images will be tagged with both. It’s not a permanent tag, and so you can’t rely on it to protect your images from copyright theft, but it does make it so that you can easily identify who shot a particular image in your library.
Dual-axis level gauge. Also unchanged is the Pentax K-3′s dual-axis level gauge function. This detects both side-to-side roll, and front-to-back pitch. Roll is displayed in the viewfinder, and on both top / rear LCDs. Pitch can be displayed only on the rear LCD.
Horizon correction. Pentax’s recent flagships go a lot further than most DSLRs, which simply show pitch, though. Like its other flagships, the Pentax K-3 can automatically correct for up to two degrees of roll in either direction if Shake Reduction is disabled, or one degree if it’s enabled. If you’re driven to distraction by tilted horizons, it’s a great feature to have.
Composition correction. Horizon correction takes advantage of Pentax’s sensor-shift system, and so to does composition correction. This is handy when you’re shooting on a tripod, and want to make very slight adjustments to composition. You can move the sensor left, right, up, or down, and rotate it by up to a couple of degrees, fine-tuning your composition to perfection.
Playback. The Pentax K-3′s new LCD monitor has a wider aspect ratio and a slightly higher resolution, and that has translated to some subtle changes in playback mode. For one thing, the number of thumbnail images shown on-screen at any given time has been changed, and now varies from a minimum of six to a maximum of 80. The display magnification is now 16x max., instead of 32x max., and there’s a new 100% quick magnification function which helps you check focus at 1:1 resolution without needing to fiddle with the playback zoom controls.
In other respects, though, things are much as before — and much as you’d expect on an enthusiast camera. You can develop raw images in-camera, compare images side by side, get a warning of bright / dark areas in images, and view both RGB and luminance histograms to confirm you’ve nailed your exposure.
Just as in record mode, the selection of playback image filters has ben changed, with four modes dropped, and four added. The new filters are the same as those in record mode: Shading, Invert Color, Unicolor Bold, and Bold Monochrome. The filters they replace, though, differ. You lose the Custom filter as in record mode, but you also lose the monochrome, color, and HDR filters from earlier cameras.
Movie capture. There are some huge changes in Movie mode, and among them all, the key change for our money comes thanks to the new image processor. There’s no more dated, inefficient Motion JPEG compression, with the Pentax K-3 using MPEG-4 AVC / H.264 compression in a .MOV container. (OK, that’s not entirely true — interval movies, which we’ll come to in a second, are still shot with Motion JPEG compression. All real-time movies are shot with H.264 compression, though.)
The Pentax K-3 also brings a much better selection of frame rates. As you may remember, the K-5 and K-5 II / IIs were limited to 25 frames per second at Full HD (1080p) resolution, and 30p / 25p at lower resolutions. The Pentax K-3 blows this out of the water, providing either interlaced 60i / 50i or progressive-scan 30p / 25p / 24p at Full HD resolution. At the lower 720p resolution, you’ll find the same selection, except that the interlaced frame rates are replaced with progressive scan 60p / 50p rates.
And with the new, more efficient compression, Pentax no longer sees the need to provide for standard-def capture, so it’s dropped the VGA resolution of earlier cameras entirely.
The Pentax K-3 also offers more intuitive movie controls. There’s no longer a separate Movie mode on the Mode dial, and you don’t use the same shutter button for stills and movies. Instead, a quick flick of the rear panel’s Still / Movie switch puts the camera in Movie mode, and the new Movie button adjacent to the LCD display starts capture.
There’s also a better selection of capture modes for movies. As well as the existing Program and Aperture-priority exposure modes, the Pentax K-3 now supports shooting with Shutter-priority or fully Manual exposure. That’s big news if you want the maximum creative control over your movies.
The K-3′s built-in microphone is still monaural, but it’s been moved to the front panel, which should provide for better audio quality since it faces your subjects. (We’re interested to see whether the new location, which is much closer to the lens, also picks up noise from the stabilization system, though.)
Whether or not that’s the case, it’s not a big deal, because the Pentax K-3 still provides for an off-camera microphone courtesy of a standard 3.5mm stereo mic port. There’s also a new 3.5mm stereo headphone port, which means that you can monitor audio levels before and during capture. The K-3 also provides levels display before and during capture, completely with a peak hold function, and separate display of left / right channels.
One thing that still seems to be absent, though, is autofocus during movie capture. That means you’ll still have to pull focus manually, or set your shoot up so as to keep your subject within depth of field. It will, at least, be easier to do so with fully manual exposure control.
There’s also still a 25-minute clip length limit in the Pentax K-3, and so if you need to have longer continuous shooting, you’ll need to look for another solution.
Another new feature, though, is the interval movie mode which was first introduced with the Pentax Q, and made its K-mount debut on the Pentax K-30. This has been reworked in the Pentax K-3, though, and now shoots at 4K resolution (3840 x 2160 pixels). If your clips are lengthy, you can expect some seriously colossal file sizes at this resolution, thanks to the Motion JPEG / AVI compression but the ability to shoot ultra high-def time-lapse video is nevertheless pretty cool.
Weather-sealing / cold-proofing. The Pentax K-3′s body is still comprehensively dustproof and weatherproof, thanks to seals at all controls and body seams. The number of seals has been increased from 77 to 92, but we wouldn’t necessarily take this to indicate a greater degree of sealing — there are simply more controls that need sealing on the newer version. Pentax’s flagship DSLRs have a reputation as among the best-sealed in the business, regardless. And the K-3 is also still freezeproof to 14°F / -10°C, and works reliably in temperatures up to 104°F / 40°C.
And it’s not just the body that’s weatherproof, either. Regardless of whether you’re shopping for consumer or enthusiast-grade gear, weather-sealed options are now available to you. The optional portrait / battery grip is sealed to the same standard as the camera body. Likewise all DA* lenses, and several affordable WR lenses covering everything from 18mm to 200mm have been weather-sealed for some years.
And now, a just announced, weather-sealed variant of the 55-300mm lens takes consumer-grade weather-sealed coverage out to everything from 18-300mm, with just two affordable weather-sealed zooms. Add in Pentax’s recently-announced weather-resistant strobes, its weather-sealed GPS receiver, and even a weather-sealed infrared remote, and there isn’t a link in the chain that can’t be used in dust and rain.
If you plan to shoot in inclement conditions, rest assured: this is truly part of a weather-sealed system.
Connectivity. Another important change in the Pentax K-3 is to be found in the connectivity department: a USB 3.0 Micro B connector, in place of the previous combined USB 2.0 PC / AV connector.
Otherwise known as SuperSpeed USB, USB 3.0 is theoretically 10x faster than USB 2.0 (aka Hi-Speed USB) — and it’s backwards compatible, so if it’s not yet supported by your PC or Mac, you can still get USB 2.0 rates.
Alongside the debut of USB 3.0 connectivity, support for standard-definition video output has been dropped. Instead, the Pentax K-3 now offers only a high-definition Type-D Micro HDMI output. We’re not yet sure if it supports uncompressed live video over its HDMI port.
We’ve already mentioned much of the K-3′s remaining connectivity, which includes 3.5mm stereo mic and headset jacks, an intelligent hot shoe, PC sync terminal, front and rear infrared receivers, and a connector for an optionally-available portrait / battery grip. There’s also an 8.3V DC input, which is unchanged from that in the Pentax K-5 and K-5 II / IIs, using the same K-AC132 AC adapter kit.
Power. The Pentax K-3 retains the same D-LI90 battery as its predecessors, but unfortunately, there’s been a significant 24% reduction in battery life. The K-3 is now capable of 560 shots on a charge to CIPA standards, down from 740 shots on a charge with the K-7, K-5, or K5 II / IIs. With no flash usage, you’ll get 720 shots on a charge, down from 980 shots in the earlier cameras. Playback time falls from 440 minutes to 370, a 16% reduction.
Battery grip. Thankfully, you can still supplement battery life by using the optional portrait grip. (And with the shorter battery life, we’d imagine it will be more popular than ever.)
Unfortunately, you’ll need a new grip: the Pentax D-BG5, replacing the D-BG4 grip which dates back to the K-7. Much like that grip, you can add second D-LI90 for double the battery life (1120 shots on a charge to CIPA standards), or alternatively you can supplement the in-body battery with six standard AA cells. (Battery life here would depend on the AA battery type.)
Either grip battery option is catered for with removable battery trays, and if you’re shooting with the D-LI90 battery tray, it also includes space to store a spare Secure Digital card.
Storage. Speaking of storage, the Pentax K-3 still writes its images in JPEG or 14-bit PEF/DNG raw formats. (The resurrection of the .PEF raw format is good news for anybody who bemoaned the inclusion only of DNG raw on the Pentax K-30, K-50, and K-500.)
A very significant change from the K-3′s predecessors is the presence of dual card slots. That catches Pentax back up with rival Nikon, which has offered dual card slots in both the D7000 and D7100. At Canon, you’ll have to step up to the full-frame EOS 5D Mark III if you want dual card slots.
The Pentax K-3 allows you to write to its dual card slots in several different ways. You can either write to the cards sequentially, first filling one and then the other, or write to both slots simultaneously for a backup, or write raw images to one slot, and JPEG images to the other slot.
The K-3 supports both the higher-capacity SDHC and SDXC cards, and the higher-speed UHS-I cards. With the latter, it will not only handle SDR50 / DDR50 cards with a bus speed of 50MB/second, but also SDR104 cards with a bus speed of 104MB/secind.
It also supports two differing wireless flash card formats: either the well-known Eye-Fi cards, or the lesser-known Trek Flucards.
Remote control. The latter provide not only for file transfer, but also for remote control. (At least, if you’re using a Pentax-branded Flucard.) That means another hole in Pentax’s offering has been plugged. Ever since the Pentax K-7, we’ve bemoaned the lack of an official remote capture solution, and now it’s available.
When shooting with a Flucard, you’ll receive a remote live view feed, you’ll be able to select the autofocus point remotely, and you’ll be able to trip the shutter remotely. It isn’t yet clear whether you’ll be able to adjust other settings, but we certainly hope so. You’ll also be able to transfer reduced-size or full-size images, and even raw files, all via standard Wi-Fi to your PC or smart device. Both Android 4.2 and iOS 6 apps will be available, and other devices should be able to control the camera via a web browser.
We’d still like to see an official tethered shooting solution — if for no other reason than that we want to see apps like Adobe’s Lightroom and Phase One’s Capture One supporting tethered shooting with the Pentax K-3 — but the presence of a wireless solution is still excellent news.
Software. The K-3 digital SLR ships with an upgraded version of Pentax’s Digital Camera Utility 5 software. We do know that it’s still Silkypix-based, but don’t yet have detailed information as to how it differs from the previous release.
Accessories. Available accessories will include the Pentax D-BG5 portrait / battery grip, which is dust / weather sealed, accepts a second D-LI90 battery pack or six AA cells, and provides duplicate shutter-release, AE-lock, AF, ISO, exposure-compensation and green buttons, as well as a preview lever and dual electronic dials. Pentax will also offer an own-branded O-FC1 16GB Flucard Wi-Fi SD card, and a 50cm long, 4cm wide O-ST1401 camera strap in red or black.
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Article source: http://petapixel.com/2012/11/22/theory-nikon-d600-sensor-spots-caused-by-scratched-shutter-curtain/
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Pentax K-3 Review -- Hands-on Preview
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