In photography, the term aperture relates to the amount of light entering a camera. Basically, it’s an opening, an incident capacity of light rays in a lens that can be widened or shortened. This opening that allows the light to pass is controlled by aperture blades (diaphragm).
F-number or f-stop:
Aperture size is determined by the “f-number” also known as “f-stop” which is the term used to express the opening size of a lens. F-number varies like f/1.4, f/2, f/2.8, /f4, f/5.6, f/8, f/11….
The smaller F-number implies Maximum aperture with a wide opening while the larger F-Number implies Minimum Aperture with a small Opening.
In a human eye, the size of the pupil increases or shrinks concerning the light outside, pupils contract themselves when there is enough light to sense or sharpen the outside objects but in a darker room, pupils expand to get as much light as to make the object conception better in a dark.
Same as a human eye, the aperture is used in the camera to manage the balance of light in accordance with the need of an image.
Exposure through aperture:
F-number describes how much the aperture is wider or small to allow light to enter into the camera. The lower the number (Larger aperture), the wider the opening is, allowing much light to enter and resulting in a brighter image. As the f-number increases (low aperture), less light passes-in resulting in darker images.
Depth of field through aperture:
Depth of field (DOF) means how much area of our image is in focus. Aperture doesn’t only mean to allow light to enter, it also refers to the percentage of an area of an image going to be in focus.
For example, if the f-number is set to small like f/1.4, means the wider opening, creates a shallow focus effect. Which creates a smaller depth of field, which means a small area of an image is at the focus. The surroundings and background are fuzzy or blur (not in focus). Generally used in portraits or simple images where the object in the foreground is shown isolated from the background. Macro photographers use it to make the viewer’s attention to the main subject while throwing the extra busy background out of focus.
A larger depth of field means to keep as much area in focus whether of foreground or background. As much the aperture is increased like f/22, the opening of the lens is smaller, less light is passing through the lens, creating larger depth of field, results in the more cleared and sharpened image as much of area is now at the focus. Generally used for landscape image where both the background and foreground area in focus.
Aperture modes and setting:
Setting aperture manually is highly preferable as it needs a slight touch to move between the f-stops. While aperture can be set digitally if you’re using an electronic lens that is compatible with digital cameras. Being a basic part of photography, the aperture button is commonly placed at an easily reachable part of the camera.
Aperture priority and manual modes are generally given where the shutter speed is concerned, aperture priority mode automatically adjusts shutter speed with aperture and in manual mode, you need to set both the aperture and shutter speed separately.