Aperture in photography or commonly referred to as a diaphragm is a measure of how much the lens hole is open which serves as an entrance for light. Usually the unit used is symbolized by the letter F.
The larger the diaphragm number, the smaller the opening, so less light enters. Vice versa, the smaller the diaphragm number, the larger the opening, so that more light enters.
Source : https://www.plazakamera.com/mengenal-aperture-kamera-pada-dslr-dan-mirrorless/
Depth of Field
Aperture is closely related to Depth of Field, which is usually abbreviated to DoF, which is a measure of how far the focus plane is in the photo. The smaller the number (the larger the aperture) the diaphragm will produce a photo where only a little is in focus, the rest looks blurry. For example, if you use an F/1.8 aperture, the focus area you get is narrower, but if you use f/22 the focus area you get is wider so that almost all objects are in focus and sharp.
Photos that use a narrow depth of field , with f 1/1.8
Photo that uses a wide depth of field , with f 1/22
To be able to get the right f settings, it is recommended that you continue to practice so that you can increase your sensitivity in determining the f value in a photo. Happy practicing, KEE friends!