Hi,
Image quality is more related to sensor size than pixel size. The reason is that IQ is most dependent on the number of photons collected. Just having more pixels will reduce the image quality per pixel but that is compensated by having more pixels.
Resolution will increase with increasing number of pixels and aliasing will be weaker. Sharpness/resolution is more likely limited by diffraction and lens limitations.
In my view the only disadvantage with many pixels is that processing time increases and so does needed storage place.
The only case this would not hold is if the high pixel density reduces the photon capture efficiency of the sensor or well capacity in the sensor is reduced. Adding more pixels adds more electronics and makes the sensor cells smaller. This would ultimately lead to less of the imagers are used for actual sensors. Also with small sensor cells, well capacity will be reduced, so DR (by the technical definition SNR equals unity) will go down.
So, a full frame sensor with the same pixel density as the 7D will have essentially the same image quality as the Canon 5DII but will enlarge better. It will not reach MFDB IQ because the smaller sensor collects less photons.
Enlargement size will be limited by lens quality. Any decent lens is sharp enough at the center at medium apertures to cope with most sensors, edges and corners may be different. Utilizing all megapixels needs cautious work, very good lenses reaching optimum performance at f/5.6, not stopping down much beyond f/5.6, exact focusing a good tripod and mirror lock up, or very short shutter times.
Best regards
Erik
Trying to overcome my natural repultion for maths and calculations, if I understand well, Canon is going to fill the FF sensors with 45MP?
What about pixel-density in IQ ? Thought that was really the most important factor.
