Monday 26 May 2014

How to process and edit raw files


Nikon D610 (with 24-85mm lens)


Shooting in raw is one of the best ways to have total control over your images in post-processing.


A raw file is the image as seen by the camera’s sensor. Think of it like unprocessed film. Rather than letting the camera process the image for you, turning it into a JPEG image, shooting in raw allows you to process the image to your liking.


Applying adjustments to a raw image is a non-destructive method of editing your photos, unlike editing a JPEG.


Want the best of both worlds? Some digital cameras will let you shoot in raw + JPEG mode, capturing the raw image while simultaneously processing a JPEG image for easy use.


What you need



  • A digital SLR or camera that can shoot raw

  • Image processing software such as Adobe Lightroom, Photoshop or the software that came with your camera


Remember that not all raw files are created equal, as different manufacturers will more than likely use their own proprietary file formats. For example, Nikon uses the .NEF extension, Canon uses .CR2 and Sony uses .ARW. Pentax generally uses the more open DNG format.


If you don’t have access to raw editing software, there are also a few web-based tools that can help, such as WebRaw and Pics.io.


For this tutorial we will be using Adobe Camera Raw and Photoshop CC, but the principles should be very similar for whichever editing program you use.


Basic adjustments


When you open up the raw image in Photoshop, Adobe Camera Raw will automatically start. The window will look something like this:



camerarawoverview.jpg


Screenshot by Lexy Savvides/CNET


From here, you can adjust values such as the exposure and temperature. Move the exposure slider to simulate the effect of adjusting your exposure in-camera. The results will be automatically reflected in the image.


Notice that as you adjust most of these settings, the histogram will also change.


Recovering detail


One of the most important reasons for shooting in raw is to be able to recover image detail in case something goes wrong. Blown out your exposure so there are white patches of highlights everywhere? You probably will be able to bring some of this detail back thanks to the raw file.


In the example below, you can see from the histogram that there are clipped highlights in the sky. If you need help reading your histogram, this article explains more.



camerarawhighlights.jpg


Screenshot by Lexy Savvides/CNET


The recovery slider is the key here; moving it further to the left will bring back detail that was lost from the blown out highlights. Extra image detail can be recovered by adjusting the exposure slider as well.


The same process can be used to bring back shadow detail in underexposed areas.



camerarawshadows.jpg
This image has a lot of detail in the underexposed shadow areas that can be brought back with a bit of tweaking.

Lexy Savvides/CNET


To recover shadow detail, use the same technique as for recovering highlights. Simply move the slider until you see detail appearing again.



cameraraw-shadows.jpg


Screenshot by Lexy Savvides/CNET


White balance


Rather than setting a white balance value in the camera, when you shoot raw you can use any white balance setting and then adjust it in post-processing. From the Camera Raw interface, choose an option from the drop-down menu that best suits your needs.


There is another tool available in Camera Raw that provides white balance adjustment — the white balance dropper. At the top of the window, simply select the white balance tool, and click on the part of the image that should be white. Then, Camera Raw will automatically adjust the colour temperature to make that component a true white. This is exactly the same as taking a manual white balance reading in-camera.


Making images pop


The examples above have mostly been working with images with quite obvious faults. Sometimes, there may be nothing wrong with your image at all but it looks a bit dull. Here is how to make an image pop with a few simple tweaks to the raw file.


Below is an image taken on the camera’s metered exposure. It looks OK, but could use a bit of work to make it look even better.



camerarawdog-normal.jpg


Screenshot by Lexy Savvides/CNET


First, let’s brighten things up a bit by increasing the exposure. I have also brought up the contrast a bit.



camerarawdog-adj1.jpg


Screenshot by Lexy Savvides/CNET


The image still looks a bit cool, so I’m going to change the white balance option to warm things up a bit. For outdoor situations, the cloudy white balance preset adds a more warmth to the scene. You could also achieve a similar effect by moving the temperature adjustment slider. I have also taken this opportunity to pull up the white value, and recover some of the lost highlights in the wall by bringing down the highlight slider.


Finally, to really make things look defined, boost the clarity slider a little bit to the right. The clarity tool looks for edges and defines midtone contrast. Use it sparingly for the best results.



camerarawdog-adj2.jpg


Screenshot by Lexy Savvides/CNET


Here is a comparison of the before and after image to give you an idea of how you can make an image pop using raw adjustments:



camerarawbeforeafter.jpg


Lexy Savvides/CNET


Once you have applied some basic adjustments, click Open Image to enter into Photoshop and continue editing as you need.


This is a basic walkthrough of editing raw images — stay tuned for a more in-depth look at raw adjustments soon.



How to process and edit raw files

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