>>4353484Ah alright, so to give a general summary:
Full frame sensors with full frame lenses give you "normal" values. I.e., you take a 50mm lens and put it on a FF body, the Field of View is basically the same as the film era SLRs; you can take that 50mm lens and put it on a film EOS and it will have the same FoV. FoV is how much of the scene we fit inside our picture. APS-C cameras only use the inner portion of that total image circle; it literally crops out the middle and discards the rest. So even if you put a 50mm lens on APS-C, we have less stuff in our shot and therefore the FoV is tighter (so long as you stood in the same spot etc.)
The reason this is relevant, is that even though the FF and APS-C camera both have 24MP, the APS-C camera is only spreading those pixels across the already cropped out "middle" portion of the image the lens picked up. Whereas the FF camera spreads 24MP across the larger image. So if you were to manually or otherwise crop the FF shot to mimic the APS-C one, you would get lower pixel density. However, FF is still superior. APS-C's advantages are size, weight, and cost.
If all you wanted was a tighter FoV, you just use a lens focal length that is tighter, say 80mm. Congratulations, you just got pretty much the same FoV, framing and pixel density as the APS-C camera shooting with a 50mm lens, but with the added benefits of a FF sensor. FF sensors are pricier and result in larger camera bodies, but give you better Dynamic Resolution and lower noise.
Dynamic Resolution refers to how effectively a camera can capture dark and bright portions of a shot while still retaining detail and not clipping (i.e. no detail). A camera with higher DR is objectively better for picture quality. Noise is an unwanted effect that looks like grainy coloured mush which is the result of not having enough light gathered during the photo shoot. Since FF sensors are larger, they gather more light, and thereby have a lower noise generation.
