>>4271969>i never said it changes shot noise, it changes overall noise (the lower part of the equation) via electronic gain, With an ISO invariant sensor it does not change e-noise. In an ISO variant sensor it INCREASES e-noise, actually decreasing overall SNR.
>Or are you trying to argue that if you keep aperture constant, SS constant but you lower ISO on stop from 12800 to 6400 you don't see any difference in your image? LMAOYou laugh because you don't understand any of this. Most sensors are invariant by 6400. So if aperture and shutter are constant then:
- SNR will be the same between 6400 and 12800.
- Apparent brightness will be 1ev greater at 12800 because you have 1ev more gain.
- You will clip highlights at 12800 that would be held at 6400.
- You might think noise is worse at first glance, but if you pull the gain back down in post to match the 6400 shot, you would see it's the same.
ISO ONLY CONTROLS GAIN. It does NOT control actual photon capture. Photon capture determines shot noise which dominates image noise. In an ISO invariant sensor gain does not affect e-noise unless you cross a dual gain stage ISO. In an ISO variant sensor, lower gain has WORSE e-noise.
tl;dr - no, you do NOT get another noise reduction by lowering ISO.
>>4271971>picking the A7R VOf course you already know that the A7R V is a relatively poor performer at high ISO. The reason is unknown. (If it was pixel size then other high resolution bodies would perform worse, but they don't.) That's why you cherry picked it. Here's an R6 and R5 showing what you would normally expect, which is a FF 2 stop advantage over mft.
