Taking one of the few recent-ish mainstream phones on this list since the subthread is about smartphone sensors: Samsung Galaxy S7 has an ISO range of 50–800 and basically all the noise values (measured in log2(electrons)) are between 2 and 3. There is a downward trend from 50 to ~300, above that it's all around 2. Other phones have similarly shaped graphs with different absolute values.

That sounds like the opposite of what GP (CWuestefeld) described. Am I misinterpreting the graph?

Lower sounds better to me, so the downward trend on a scale called "Input-referred read noise" sounds like it is tuning the Signal to Noise Ratio (SNR) on the sensor rather than just multiplying the sensor's output value, and it stops doing that above ~300 ISO. GP described that it would be a linear multiplier up until (for many cameras, not specifically smartphones) ~1600 ISO and after that it would be tuning the SNR. Do smartphones behave differently for some reason or am I misunderstanding something?

(It doesn't seem as though the absolute value says anything about the quality by the way, as a 10th gen Apple phone has a much lower value on this "noise" scale than a 12th gen one. The page does remark "raw values are not appropriate for comparing camera models because they are not adjusted for area", so this is probably that.)

I'm not an expert, but I think phone camera sensors really are that different from camera camera sensors, presumably (going out on a limb) because of tradeoffs they make to get good quality from small sensors. The sensors in top phones are about the same size as in the smallest cameras, and way smaller than in the cameras GP is thinking of.

> That sounds like the opposite of what GP (CWuestefeld) described. Am I misinterpreting the graph?

No. I was stupid in what I said above, getting the direction wrong. Where I said, "...will reset to a lower snr", I should have said HIGHER.

Ah, got it! Thanks for confirming! And it's definitely not stupid: I didn't even know of this concept, so I learned something today thanks to you :)