>>3942069The thing is, a higher res sensor (smaller pixel size) will "notice" diffraction earlier and start losing resolution earlier, than a lower res sensor.
Say the high res sensor starts dropping at f/11 and the lower res one at f/16.
But since it starts at a higher starting point, it will still have more resolution at f/16 than the lower res sensor.
So most of the time it's not worth comparing diffraction between different sensors, unless you make it clear that even past its diffraction limit, the higher res sensor will still perform better at a given aperture, say f/16, than a lower res one at the same aperture which happens to be its diffraction limit.
I mention this because I've seen many people miss that point and thinking the lower res sensor will match or outperform the high res one if the latter is past its diffraction limit.
And all that is given an idealised perfect lens. In physical lenses, the lens will have its own diffraction limit which is a hard upper ceiling at the resolution.
Which makes mentioning theoretical diffraction limits of sensors kinda meaningless.
When talking about different lenses, your system will perform the best at the *lens'* diffraction limit, not the sensor's. You might very well have better performance *beyond* the sensor's diffraction limit, because the lens' diffraction limit is further down.
Comparing different systems with different res sensors and lenses, not much can be said about diffraction *in general* without knowing the lens' diffraction limit.
And practically, as long as you don't do something utterly retarded like going beyond f/22 in 35mm (here the format matters not because of size, but because of the different diffraction limits - *usually* - of 35mm vs say large format lenses), you're gonna be fine.
