Restating the Q formula from this post with the Bayer CFA correction from yesterday’s post:
Qbayer = lambda * N / (pitch *1.7)
Where lambda is the wavelength of the light in micrometers, N is the f-stop, and pitch is the pixel pitch in micrometers.
For 0.5 micrometer light,
Qbayer = N / (pitch *3.4)
Since a Q of 2 means that the sensor and the lens are “balanced”, we can relate f-stop and pixel pitch for balanced systems:
N = 6.8 * pitch
pitch = N / 6.8
For a setting of f/6.8, we want a 1 micrometer pixel pitch. For a setting of f/8, the pixel pitch should be 1.18 micrometers. These numbers are much finer than any available sensors sized at micro 4/3 and larger.
If we think the correction factor should be one,
Q = lamda * N / pitch = N / (pitch * 2)
And for a “balanced” system
N = 4 * pitch
Pitch = N /4
At f/8 we want a 2-micrometer pixel pitch, still finer than currently available for any available sensors sized at micro 4/3 and larger.
The bottom line is that any interpretation of applying image system Q and the idea of the balanced system to Bayer arrays gives the result that, for fine lenses, resolutions of at least a binary order of magnitude higher than currently available are desirable. This argues for 200+ megapixel full frame sensors.
This is at variance with conventional wisdom.