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I did a deep dive into digital camera sensors, and I want to check my notes so far. Which of these did I misunderstand:
> A. ISO is actually a gain nob, has no effect on the actual CMOS sensor, and the only reason we don't have a continuous dial on the damn thing like a radio is because of our film tradition. On an ISO invarient camera body, it's also no different than adjusting the slider for exposure in post production.
> B. None of the major manufacturers actually follow the International Standards Organizations amounts for a common gain dial as proposed in ISO 12232:2019. This probably wouldn't matter if they just called it the thing the new-and-improved exposure compensation dial and we were done with it.
> C. Since ISO no longer has any real effect on how much light the camera sensor detects, the very simplified exposure equation variables are now aperture, shutter speed, and noise-to-signal-ratio, and assuming you have an ISO-invariant camera, there's nothing you can do for that SNR side of the equation save buying a sensor with better SNR.
> D. Given a set number of photons (p) streaming onto a sensor, photosite surface area is the big determiner for how much light your sensor detects. In other words, given 36mm x 24mm sensors and all other things being equal, a 16mp camera will gather more light per photosite and result in a stronger exposure compared to a 24mp camera, but at the expense of image resolution in line pair / mm
> E. Given lenses that focused the same amount of photos onto each sensor and all other things equal, a 24mp 36mm x 24mm and 12mp 25mm x 17mm would have roughly the same exposure, due to similar sized photosites.
