As cameras and camera-phones gain sufficient resolution so that increases in pixel count are no longer critical, what will further increases in sensor capabilities be used for? So far, there appear to be a few answers to this question. The first is that multi-layer sensors such as the Foveon chip become less important, as we now have resolution to waste. Lytro, on the other hand, proposes to use the extra pixels to capture multiple depths of field at once, and allow you to choose your focus after the fact. Clever, but a bit gimmicky. Nikon’s more recent answer is: More Cowbell! as they move to a 36MP sensor in the new Nikon D800.
Canon, on the other hand, may be holding steady, if it releases its Canon 5D Mark ll replacement (rumored name: Canon 5Dx) at the same 22MP resolution as the current version, and instead uses the extra capability to boost dynamic range and speed, and to reduce noise. This choice would sit well with videographers and time lapse photographers, who stand to gain nothing by increased resolution, but lots from increased sensitivity. Still photographers (are there still any still photographers; doesn’t everyone shoot at least a little video?) may also prefer the dynamic range and speed increases over what for most uses is excess resolution. If my f/4 lenses are now as fast as f/2.8 lenses on the previous body, then I can carry a lot less mass, and pay a lot less for lenses. Another possible reason for Canon and Nikon making different choices would be that Nikon’s unique lens surfacing techniques may allow them to push resolution further, while Canon might well exceed their lens resolution with a large increase in sensor resolution; which would mean that targeting speed and dynamic range improvements make more sense, if resolution gains could not be supported by the glass. And lets be clear: most lens, under most conditions, are struggling to produce razor sharp 22MP captures: few circumstances outside the studio could manage more.
But what about today’s new buzz: a 41MP camera phone, with a Zeiss lens? Let me start by saying that improved lenses in camera phones are much appreciated, as are larger sensors. The improvement from the 5MP iPhone 4 to the 8MP iPhone 4s is significant. Apple produces only one phone per year, and must aim it at the least common denominator, so a photographer-specific iPhone is not a likelihood. Making a big bulge on the back of the iPhone for a camera is not likely to suit general tastes, either. So far, add-on lenses are the iPhone photographer’s friend. But Nokia is struggling for market differentiation and market share; having vastly more megapixels than anyone else is certainly a headline capturing technique. Having a brand-name lens (however diluted that brand may now be) also will catch a lot of attention. The real question is: what resolution and image quality this will produce? Nothing close to a 41MP medium format or DSLR with professional lenses, its safe to assume. But more resolution than most current 5 to 8MP phone cameras, without doubt. One interesting note is that it will have a 5MP mode, for practical, real-world shooting, and the downsampling should reduce noise in the process. That choice may say more about the real-world resolution of the camera than the headline catching 41MP number.
But from a practical point of view: I can carry a wide range of pocket-size dedicated cameras. I will have an iPhone in my pocket no matter what (Nokia does not offer what I want in non-camera features) so a Nokia camera-phone would simply be a Nokia camera to me.