How to find the megapixel usability of a lens.

ecka84 says:

There’s this “p-mp” concept of the “Perceptual MegaPixels”. Which means that the image contains a lesser amount of the actual data, visually useful real world information. Perfect lenses do not exist. Therefore it is pretty much impossible to get 24p-mp out of any 24mp camera-lens combo.
9p-mp sounds about right for a cheap kit lens in perfect lighting conditions or a lab test bench. However, it doesn’t mean that a higher resolution camera cannot produce more than 9p-mp with the same lens. Lens resolution isn’t a capped number. For example, same lens on a 20mp camera could get you 8p-mp, while on a 32mp camera it could get you 12 or more p-mp.
Usually, larger sensors are more efficient at “Perceptual MegaPixels”. They are more “forgiving” for the optics. Basically, the same lens produces sharper (also cleaner and more contrasty) images on Full Frame than on APS-C.
So, it’s easier to choose the right camera first and stop worrying about the lenses. It makes a lot more sense that way. I mean, if something like 6p-mp (3000×2000) is enough for you, then no need for better camera and optics. Plus, the viewing size is an important factor. APS-C and m4/3 can do high quality A3 size pictures. A2 might require a better and more expensive lens. Then a 20-26mp Full Frame can do A1 size with rather “mediocre optics” no problem. While 40+mp Full Frame can do A0, or more, with a premium lens.
I find the A1 size to be optimal, for now. Specially when the Full Frame with “mediocre optics” (small budget primes) is cheaper than quality optics on crop. I prefer nicer images than fancy, pretentious gear.
Originally posted 11 hours ago. (permalink)
ecka84 edited this topic 11 hours ago.

wbyoungphotos says:

Lens reviews are a good way to find the resolution of you optics,
in terms of so many lines per inch it can resolves.
Normally the L lenses do a good job.

A good lens requires a good sensor to work together,
the size and spacing of the pixels are important in capturing the
information delivered by the lens.

So the prices may indicate the quality of the gears.
8 hours ago (permalink)