This document discusses three key manual camera settings: aperture, shutter speed, and ISO. Aperture refers to the size of the opening in the camera lens and is measured in f-stops, with higher f-stop numbers corresponding to smaller aperture openings. Shutter speed determines how long the camera's shutter remains open when taking an image. ISO controls the camera's sensitivity to available light, with higher ISO numbers making the camera more sensitive. Examples are given comparing images taken with different f-stop settings.