« on: January 21, 2013, 12:17:47 AM »
Let us say that you have a APS sensor 24Mp with the same S/N as a 24Mp 24x36 sensor then it is an optical question, it is hard to make a APS lens 1,5 1,6 times better which is require compared to 24x36mm lens.
This is incorrect.
Because there will be less absolute magnification for a same-sized print with the larger format, even if the sensors have the same pixel dimensions, the larger format will be sharper and have less noise. Again, always assuming all else is comparable, including a longer focal length lens for the larger format.
Assuming M.R. means signal to noise ratio by S/N, then he is correct. Actually, the linear resolving power of the lens needs to be increased by the crop factor, and the absolute resolving power of the lens needs to be increased by the square of the crop factor. But this is all based on an imaginary hypothesis, an APS sensor with the exact same S/N ratio as full-frame. Anything is true if the hypothesis itself is false.