The Exciting World of Modern Mirrorless Cameras

[digitaldog]

Andrew,
I think this is all basic stuff. We all know that less light reaching the sensor results in more noise, which is particularly noticeable in the shadows.

I honestly don't know what 'we' all know. Someone wrote: "then increased noise from a high ISO will result" which was corrected, nothing more.

In common language, 'cause and effect' are often confused.

Agreed, the sentence above in quotes is an example. 
Here's another silly one: "then increased noise from a high Aperture will result". 

[PeterAit]

Because how you don't control the exposure and allow the capture to be under exposed. Under exposure causes noise, not ISO.
Want to see a higher ISO produce lower noise than a lower ISO? 
Setting ISO speed does not change the sensitivity of the sensor to light like volume control does not change the sensitivity of a radio. In both cases the setting (ISO or volume) controls only the signal processing, while the input stage (sensor, antenna) provides the same input signal. When the ISO setting is cranked up, automatic exposure results in more noise - automatic exposure, in this case, decrease the exposure (that is, the combination of aperture and shutter speed is set to allow less light to be captured by the sensor). Less exposure, less light, more noise. A higher ISO may provide less noise (due to exposure). A doesn't (always) cause D. C can cause D if you let it.

I don't buy it. I defy you to describe a real world situation, where the goal is a properly exposed image, where A does not cause D.

[digitaldog]

I don't buy it. I defy you to describe a real world situation, where the goal is a properly exposed image, where A does not cause D.

I already did (and have done so for 4+ decades) on film (transparency no less) and digital, for a living.
"Facts are facts and will not disappear on account of your likes." -Jawaharlal Nehru

[Rob C]

Digitaldog, thanks for taking the time to respond to my questions; that link you provided was an eye-opener. I had never questioned the truth of the “triangle” with film, though it had not been called that in my time on the job. I thought it would be the same with sensors.

The take-away I get is that no, one cannot equate exposing film with exposing a sensor. Basically, I think it’s not the same thing as simply using a faster film stock, but more akin to pushing film. I must try out that three-exposure experiment you suggest.

Thank you again for your time.

Rob

[digitaldog]

Digitaldog, thanks for taking the time to respond to my questions; that link you provided was an eye-opener.

Another good video (If I didn't already post it):
https://www.youtube.com/watch?app=desktop&v=il28la8DRCU
Kind of long but worth the time to view.

[digitaldog]

Cause and effect indeed:

Once More into the Negatives of the “Exposure Triangle” Dear Friends, Abridged Version:

The triangle model states that noise rises as a result of ISO being increased.
This is tosh, it’s worse than saying that “well, the wind is blowing because the trees are swaying” (in that case, all that’s happened is a mix-up of cause and effect), it’s like saying that the sea is salty because of all of the lox swimming in it (which goes beyond just confusing cause and effect, because here the “cause” is an absolute invention – a salmon swimming in the sea isn’t salty, while lox, a product of brining salmon fillets, doesn’t swim in the sea. It doesn’t swim at all).
The model warns against raising ISO “because of increases in noise”.
Another lie – everything is exactly the opposite; when the exposure is fixed, not only will raising ISO not worsen the signal-to-noise ratio, it may noticeably improve it.
The model says, right in the name, that ISO is a part of exposure, which is absolute balderdash.
The model presents ISO as a part equal to exposure itself (highlighted by the fact that the sides of the triangle are equilateral), which is, again, absolute nonsense.
The model does not at all underscore the leading role of exposure in controlling noise and dynamic range. In fact, the model hides it.
Exposure is much more important, and it needs to be set first so as to be as high as possible, while ISO is set afterwards so as to reach the desired lightness, but without clipping the elements in the highlights that are important to the composition of the scene. In this case, even the simple in-camera histogram isn’t unhelpful, because a mistake towards insufficiently high ISO leads to less, if any, additional noise than a mistake with the exposure due to a premature clipping indication taken “from the JPEG”.
The model suggests that one consider the goal of exposure to be lightness.
Absolute hokum. Lightness only appears as a result of rendering and processing, and all of that happens after exposure. Exposure and lightness are different physical quantities, with different units of measurement – how can they be interchanged?

https://www.fastrawviewer.com/blog/mystic-exposure-triangle

[Rob C]

Another good video (If I didn't already post it):
https://www.youtube.com/watch?app=desktop&v=il28la8DRCU
Kind of long but worth the time to view.

Thanks again for the new link.