Hi all,
I thing that we should all agree on few things:
1. When we discuss the sensor and pixel quality, we should stay focused on that. Maybe one camera is better on many issues (handling, focusing etc.) from another one, but this does not mean necessarily that it gives better image quality sensor-wise. Of course all other issues might, or will allow the photogapher to capture a better image in the first place.
2. Sensor pixel technology changes continuously, so equal or better results can be achieved from newer sensors, even if their individual pixels are smaller.
3. Given the same technology is used for 2 sensors (this, most times, can be related to model release time), the bigger the individual pixel size the better.
4. So, unless a radical new technology is discovered for sensor making, we should expect that gradually, the individual pixel size will be decreased (more megapixels), with better image quality.
5. The critical question is if the rate of increasing the megapixels in newer models is following the technological capability, to achieve at the same time better image quality.
MY VIEW IS THAT:
For the moment, best image quality as regards Canon can be obained from 5D Mark II, 21 megapixels. This is one year old model, so I assume that same quality can be obtained today from a camera with slightly smaller pixel size. I believe that ID Mark IV, is following that, with a slightly smaller individual pixel size (about 27 megapixels full frame equivalent).
7D has pushed things much futher with full frame equivalent of 46 megapixels. I believe that this is way too much to retain a quality even close to 5D Mark II of 1D Mark IV.
I also believe that it is way too much even compared to 40D, and Canon should have gone from 10 mp of 40D (26 mp full frame equivalent), to maybe 12 mp for 50D (31 mp full frame equivalent), and to maybe maximum 14 mp for 7D (36 mp full frame equivalent). This way the image quality would have been quite close to 5D Mark II and ID Mark IV.
As I said before, other things apart from sensor quality are also counting, so I am sure that 7d is better than 40/50D in many ways, but here I discuss just sensor and pixel quality.
Thanks