Adjust ISO by stops and judge how much image noise to expect.
Every ISO stop doubles sensor sensitivity, so the new value is the current ISO times two raised to the number of stops applied. Raising ISO recovers exposure that shutter or aperture cannot provide, at the visible cost of noise that grows with sensitivity.
ISO Sensitivity
New ISO = ISO x 2^stops
New ISO = ISO x 2^stops Every ISO stop doubles sensor sensitivity, so the new value is the current ISO times two raised to the number of stops applied.
Raising ISO recovers exposure that shutter or aperture cannot provide, at the visible cost of noise that grows with sensitivity.
This calculator takes 2 inputs: Current ISO, Change. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.