Wednesday, 9 July 2014

Sony"s curved sensor could revolutionize low-cost cameras

It’s already becoming harder for a layman to tell the difference between a high- and a low-quality camera. Given the right settings and conditions, your average smartphone camera can take some seriously impressive shots — in fact, by far the biggest impediment to smartphone dominance in all but the highest-end of photography is the simple, frustrating fact that lenses are hard to miniaturize.

A camera can only resolve the light that falls on its detectors, and thus far there’s been no way to have both powerful and compact lens arrays. Now, Sony hopes to get around this fact by tailoring not the lenses to the smartphone economy, but the sensor that lies beneath it. Above, the first promotional shot taken with the technology shows the clarity it can bring.

Basically, any one lens placed in front of a flat sensor is going to introduce a form of image distortion known as Petzval field curvature, which describes the fact that light rays will be deflected a non-standard amount depending on how far their trajectory is from the flat focal plane. Put more simply, the sharper the incoming angle of the ray, the further from the lens’s focal point it will actually fall. Most high end cameras counter this effect directly, using multiple lenses to re-bend light back where it ought to go, or by doing automatic computational work on the image after collection.

Now, the sensor that actually collects these light rays could be tailored to naturally offset the field curvature effect, and that could bring much better camera performance to much smaller — and cheaper — models.

The curved sensor itself. Note that the curve is really quite mild.

The curved sensor itself. Note that the curve is really quite mild.

Simplifying lens design would be perfect for bringing increased focal length to increasingly skinny smartphones, but there are also downsides. A curved detector is inherently less able to resolve zoomed images, and it will probably fall short of Sony’s top-shelf, 24-million pixel camera tech. These basic issues with curved sensors are offset by the simplicity of design. Luckily, lower-end camera users are the least likely to want the features that confound curved sensors, but they will still limit the technology’s possible applications in the photography world.

curved camera 2Remember that you’re actually already quite used to using curved photo-detectors in your everyday life — via your own retinas. The human eye (and indeed all eyes, so far as I’m aware) uses a curved detector to (presumably) offset the field curvature and let us resolve the world accurately with a relatively simple lens design. Imagine how many more eye problems humans would have if we had four independent muscle groups trying to flex and un-flex four different lenses all at the same time. It’s much better this way.

Whether we see the same curved dominance emerge in the camera game will depend entirely on how well Sony’s early curved competitors do with photographers and budget-concious selfie-snappers alike.

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