What is Aperture (F-Stop) and how does it work?
Aperture is how a lens controls the amount of light that comes through into the camera. F-Stop is a description of how much light is being allowed in. The smaller the F-Stop value the larger the opening (aperture). Aperture size is usually calibrated in f-numbers or f-stops. i.e. those little numbers engraved on the lens barrel like f22 (f/22),16 (f/16), f/11, f/8.0, f/5.6, f/4.0, f/2.8, f/2.0, f/1.8 etc.
Aperture is the diameter of the lens opening. The larger the diameter is the more light will reach the film or digital sensor.
As you close a lens each F-Stop cuts the amount of light allowed through in half. When a lot of light is coming through you will get less depth of focus. This is good for isolating a subject to make it stand out from the background. The background will be blurred.
To vary how much of the photo is in focus adjust your aperture (F-Stop)