They Told You Wrong About ISO

Many of us have a wrong idea about ISO settings. I will just say they told you wrong about ISO. It was a misunderstanding. Whoever “they” are.

Statement of faith
It is stated as a “strong suggestion“, especially when we are learning landscape or portrait work. Never shoot with ISO over 100. Maybe it is stated as only shoot at the native ISO setting for your camera. Either way, these are given as rules.
I hate rules, especially for my art. Rule of thirds. Rules of composition. Never put the subject in the center. Never shoot at midday. Always use a tripod. The list goes on.
Like with religion, most of the so-called rules are based on good ideas, but over time they are repeated as commands and the underlying reasons are lost. Just do it. (I don’t think that is what Nike meant.) The rules become a statement of blind faith that cannot be challenged.
What is noise?
All digital cameras have noise. Noise is randomly generated in the sensor and in the electronics of the signal path until the...