Then we come to the all too familiar and all so reasonable-sounding, â€œOh, but I am a landscape photographerâ€ gripe. We are at the threshold if not well beyond lens resolution with some of the current sensors and lens combinations. Just adding more MP to a cramped image circle is simply taking a fuzzy image â€œunitâ€ projected by the lens and projecting it on 3 pixels when one pixel would have done it just as much justice. There is no additional information to be gleaned from more pixels. This is besides the physics of the light gathering power of pixels of varying sizes and all that good stuff. Original resolution for the area in which the image is projected is limiting (a lot of impressive â€œlines/perâ€¦.insert-awesome-math-terms-hereâ€ technical discussions are out there but I am trying to keep this to where the guy driving the duster in a 25inch wheel will understand ;}).
@RayS2121: While I understand the humorous point to your post, I think you are entirely wrong about sensors out-resolving lenses. To my knowledge (I'll see if I can find the reference), Canon's newest L-series lenses (mark II's and newer releases from the last few years) can resolve up to around 45mp worth of resolution in a FF image circle. Granted, not every single canon lens can resolve that much detail, however there are quite a few L-series lenses that are purported to support high-MP resolution. Canon seems to be dedicated to producing lenses with high resolving power on into the future as well.
I also think you may be confusing the pixel size of compact cameras with the pixel size of a full-frame camera. The 21.1mp 5D II sensor has an 6.4 micron pixel, vs. an average of 1-2 micron pixels for point and shoot cameras. Comparing the 7D 18mp sensor with its 4.3 micron pixels, which takes superb images with incredible sharpness, the 5D III would have to have a 46.7mp sensor to have the same size pixels. Here is the (far from "obscurest") math, in case you doubt:
Target Pixel Size = 4.3Âµm
FF Sensor Area in mm = 36mm * 24mm = 864mm^2
Pixel Area => 4.3Âµm * 4.3Âµm = 18.49Âµm^2
Pixel Area in mm => 18.49Âµm^2 / (1000Âµm / mm)^2 = 0.00001849mm^2
Pixels per Sensor Area => 864mm^2 / 0.00001849mm^2 = 46,727,961.06 pixels
If Canon's statements about their latest L-series lenses resolving up to 45mp is true, then a 5D III with a 46.7mp sensor (which is the same density as the Canon 7D 18mp APS-C sensor) would be at the limit. Thats not surprising, and it gives more credence to the 7D being an 18.1mp sensor, as IT TOO is right at the maximum resolving power of Canon's current lenses, and pushing pixel density beyond that wouldn't provide much benefit (except perhaps minimizing aliasing and moire). That would also mean a 26, 28, or 32mp 5D III is most certainly well within bounds, providing better resolution (which can't be beat when you need to blow your prints up to immense size...post-processing interpolation doesn't hold a stick to native resolution), and still potentially leaving room to improve ISO and other sensor characteristics. Here is a useful answer on a forum that explains megapixels, and how increasing resolution is rarely ever "bad", it simply provides diminishing returns after a certain point (45mp most likely with FF 35mm sensors):http://photo.stackexchange.com/a/14776/124
It should also be stated that high ISO performance is NOT a necessity when shooting landscapes...I shoot exclusively in ISO 100 or 200 for my landscapes. Dynamic range is usually managed with optical filtration such as polarizers, graduated neutral density filters, etc. (Better sensor DR can be achieved with improved sensor fabrication techniques such as better micro-lensing, higher capacity wells, lower-noise readout electronics, moving electronics out of the light path to the photo diode, etc.)
I'm certainly not against Canon meeting the cry of many professional photographers who are asking for better ISO performance. They certainly did so with the superb specs of the 1D X. I'm not at all against Canon meeting the needs of sports and action photographers with high FPS rate cameras like the 1D X and the 7D. However I do think Canon needs to listen to their entire customer base, and not ignore the huge community of photographers, be they landscape, macro, studio portrait, etc. photographers who still do care about resolution and cropping power AS MUCH
as they care about other factors like noise and AF performance. Making every camera in the Canon lineup cater to the low-res, high-speed, low-light photographers and cinematographers eliminates a position in their camera lineup that NEEDS to be filled. I, and I'm sure many other current 5D II owners, would be perfectly happy with the 5D III staying as a 21.1mp camera, so long as the AF system was improved, noise was lowered, and other factors of the camera were improved (a 4th custom dial mode in favor of the default automatic mode, for example?)
While you may not need high resolution camera yourself, some people DO, and calling those who do "chrome rim fanboys" doesn't service anyone. There are existing niches that are fulfilled by high resolution full-frame DSLR cameras, and it doesn't serve Canon well to ditch that huge market.