ISO, Aperture and Shutter are known as the “exposure triangle”.
If you know how to control or adjust these elements, taking well exposed photos will not be a problem for you.
Understanding the purpose and value of exposure is a must for photographers, particularly beginners who are serious about developing their craft.
ISO value is determined by numbers: the lower the number, the lower the sensitivity to light. Depending on your camera, the lowest value is 50, 100 or 200.
Photographers need to know and understand proper ISO settings.
The usual numerical values for the f-stop are 1.4, 1.8, 2.0., 2.8, 3.6, 4, 5.6, 8, 11, 16 and 22.
When you adjust the aperture, note that as the numerical value — a deeper portion of your photo will be in focus.