The in camera histogram is at best an approximation of the raw histogram because the in camera histogram is based on the rgb values processed from the raw data.
For a given scene luminance the in camera histogram will vary depending on variables like the metering mode, the WB setting, the camera's 'picture style' settings set by the user etc.
Simple. Because photography is all about ISO. That's why cameras have an ISO button or a dial, and lots of other ISO features. Photographers should always set their ISO first and let the camera worry about everything else automatically.
To read the above reinforces my opinion that the number found on film canisters should never have found it's way into the world of digital camera adjustment.
Setting a higher ISO number is telling the metering system to give less exposure. It's the same as Exposure Compensation but also tells the JPG engine to try to reduce the damage.
It gives less camera shake but more noise.
I didn't register, so I didn't get access to his "cheat sheets" but he actually isn't promoting the exposure triangle on his teaser homepage. In fact, he goes to some pains to explain that the exposure triangle is "wrong". It appears he's using "exposure triangle" as a kind of internet search honeypot to attract misinformed/novice photographers to his training stuff.
On the other hand, this makes more sense: exposure-triangle.com/#exposure_in_photography
(Scroll down to “What are the components of exposure” - brightness of the scene, aperture, and shutter speed)
Still contains the myth that ISO is 'the gain'. In any case, what is a beginner supposed to make of 'gain' without explanation? What is being 'gained'?
without gain you have no image. how many OP amps are before ADC 😊 in fact the photo diode voltage/charge isnt the voltage thats even sampled.
An operational amplifier is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an op amp produces an output potential that is typically 100,000 times larger than the potential difference between its input terminals.
ISO IS THE GAIN
The truth is, it’s much easier than that. ISO is the gain that is applied to the amount of light your camera sensor has “recorded”. And being exactly that, the gain, it has nothing to do with exposure. It is applied by the cameras processor long after the shutter has closed.
Nevertheless, the gain has an influence on image brightness
At base iso many cameras apply no gain and still output an image.
In the PAS modes raising iso maintains the same image lightness because either shutter speed or aperture are adjusted to reduce the exposure* by the same amount thus maintaining the same image lightness.
* exposure. - amount of light that struck the sensor per unit area while the shutter was open.