Even my almost 5 years old Galaxy S9+ has aperture. Surely something better came out since.
This is true for some cameras, but certainly not all. Many cameras, especially pro or pro-sumer grade, have non-linear ISO. That is, there are ranges for which it behaves linearly, but typically there will be some range - say the minimum up to 1600 or something - where it behaves as a linear range, and then the next setting up from that (where the settings are typically 1/3 stop) will reset to a lower snr. (And yes, that does imply that in such cases it often yields better results to go up by one or even two clicks in ISO)
I'm not sure if there any camera-phones that behave this way, though.
How does it magically make more photons fit the sensor..?
And why wouldn't you use that same magic at lower iso gain factors?
Many cameras let you set the ISO in 1/3 stop increments, but if I recall correctly, many camera manufacturers just keep the sensitivity at the base stops and adjust the brightness via software.
So shooting at ISO 250 really means ISO 200 (underexposing what you requested) but then adding a third stop equivalent of brightening to the digital file. Conversely, using ISO 160 actually means the camera is using ISO 200 (overexposing) and lowering the brightness in software.
What this means, at least 10 years ago when I was more in tune with the photography world, is that people would prefer to shoot at the [base ISO stop - 1/3] levels to because those were the levels with the least noise near that exposure setting. The cost is you risk saturating more pixels in the highlights.
And for the same reasoning, the ISO setting s 1/3 over the base stops were typically avoided as they were noisier, albeit with slightly more dynamic range.
See the "ISO-Invariance and Downstream Electronic Noise" part here: https://www.lonelyspeck.com/how-to-find-the-best-iso-for-ast...
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.)
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.
You're still multiplying what is the photo-count or shotnoise
Didn't know there is technology built on top of that... Does changing the capacitance increase the sensitivity somehow? I guess then the question is.. why isn't that always enabled. There must be some downside to it
The pixels output voltage is the charge (number of photoelectrons) divided by the integrating capacitance. Reducing the capacitance increases sensitivity at the expense of full-well capacity - because the saturation voltage is reached earlier. That’s the point at which highlights blow out.
The advantage of increased sensitivity at the integration node is that all downstream noise is applied to a larger signal, so SNR is improved.
I just upgraded to an Olympus OM-D E-M1.3. Olympus has, unlike most manufacturers, in-body image stabilization. That means that there are tiny actuators moving the sensor around to offset shaky photographer hands. Doing the stabilization in-body gives some other nifty side effects.
Olympus cameras over the past several years have a "super resolution" mode that uses this. My sensor is only 20MP, but using super resolution I can get 50MP or 80MP (on a tripod) out of it. The camera accomplishes that by using the IBIS system to move the sensor by fractional pixels and combining them as you describe. And as you note, this in turn has the side effect of cutting noise.
I was just taking advantage of this a couple weeks ago out at Fort Davis, TX, near the McDonald Observatory, which has some of the darkest skies in the continental USA. Astrophotography is notorious for causing headaches with noise, but this technique goes a huge way to cutting that down with zero extra work from the photographer (except that the shot takes 9 times longer to record).
:(
That you want to shoot RAW is pretty much covered in day 1 of intro to digital photography. The only exception to the rule is when you need super-fast frame capture rate, and the bandwidth to storage of much larger RAW files interferes. This is typical of folks shooting sports.
ISO is basically a linear gain that's done on the sensor. As long as you aren't blowing out your photo and loosing information, it basically makes not difference if you do it in sensor or later while editing
So the only variable left is the shutter speed - which is basically directly dictated by the amount of light you have. You try to get as much light as you can without blowing anything out. This is how you get the most information. You can decrease it to get faster shots with less blur, at the cost of more noise
So it all boils down to basically one "slider"/variable between blur and noise