3. Properties of equivalent camera systems
A reference camera and a (true) equivalent camera produce respective images (assuming using ideal lenses on both cameras)
which share the following properties (assuming type-1 equivalence):
Perspective
Field of View
Defocus blur, incl.:
Depth of Field (subject depth appearing focussed in a printed photo)
Background blur (blur of (infinity) subjects when out of focus)
Diffraction effects (blur due to diffraction)
Detail, resolution, number of pixels
Image noise (pixel noise due to photon shot noise)
Dynamic range
For this reason, it is impossible to tell the images apart. Which in turn means that sensor size is notan image property. Which in turn means that two camera systems with different sensor sizes must firstbe set-to / used-with equivalent parameters before they can be compared. Because otherwise, we are onlyseeing the inequivalence of choosen parameters and cannot learn anything from a comparison, except that, well cameras haven't been equivalent what was known á priori.