[killjoywashere]

> the relevant metric is what I call “photographic bandwidth” - the information-theoretic limit on the amount of optical data that can be absorbed by the camera under given photographic conditions (ambient light, exposure time, etc.).

You mean, "resolution"?

[jsmith99]

'resolution' is usually used just to mean the number of pixels: nothing about how much ligh they capture or what sort of lens and processing.

[wnkrshm]

Talking about optics, optical resolution is also a thing, i.e. whether you can resolve a certain target like a grid of micrometer-sized bars under a microscope.

Edit: That kind of resolution is induced by the optics and not by the sensor (if your optics can resolve the target, you can always add more optics to magnify the image if you have a low-pixel-resolution sensor).

Edit2: The poster you replied to is right that optical resolution is a constraint in terms of information that can be reconstructed after being imaged through a specific optical system.

An optical system filters light in phase space (imagine a space of position, angle and intensity of light in each point of the optical system, in a geometrical optics picture) and since some components are cut off, you cannot reconstruct an image to arbitrary fidelity, you lose information (or are stuck with a certain optical resolution).