Aperture is defined as the opening of the lens on your camera. Understanding this can allow you to control the depth effect in your photography.
Aperture displays in f-stops. The smaller the number the wider the lens opening is. So f/1.8 means a larger opening than f/16.
When it comes to depth effect the smaller the opening, the more in focus your photograph will be. For example, f/11 or higher is ideal for landscape photography. While f/5.6 or lower is ideal for portrait photography.
For example, the photos above show the effects of increasing the f-stops. The focus is on Big Ben.
For example, the photos above show the effects of increasing the f-stops. The focus is on the giraffe.