Aperture, in its most simple meaning, is an opening in the lens. It regulates the amount of light passing onto the film inside the camera, the moment the shutter button is pressed. One can compare Aperture to a hole. The larger the hole the more light that gets in – the smaller the hole the less light gets in.Aperture size is usually calibrated in ‘f-stops’. How often have you seen in your camera settings, something like f/5.6, f/22 etc? Each of these values represents one time the amount of light either more or less in quantity. Moving from one f-stop to the next doubles or halves the size of the amount of opening in your lens and thereby regulating the amount of light getting through it. Any kind of change in your shutter speed, one stop to the next doubles or halves the amount of light that gets in also – this means if you increase one and decrease the other you let the same amount of light in.
There is one thing related to Aperture and f numbers is that a smaller f number, such as f/2.8, is in turn a much larger aperture than the bigger f number such as f/22. Confusing right, let me summarize it for you:
Large Apertures (in which lots of light gets through) : Small f stop numbers like f/2.8, f/4 etc.
Small Apertures (in which less amount of light gets through): Comparatively larger f stop number like f/8, f/22 etc.
Depth of Field
Most noticeable result of fiddling with apertures is the Depth of Field (DOF) that your shot will have. Depth of Field basically is the amount of your shot which will be in focus. Large DOF means most of your image will be in focus where small DOF means only some part of your image will be in focus.
Aperture has a very big impact on the depth of field, Large Aperture (Smaller Numbers: f/2.8 etc) will decrease your DOF that means very less of your image will be in focus whereas Small Aperture (Larger Number: f/22 etc) will increase your DOF meaning large portion of your image will be in focus. The amount of DOF you would want in your image will be depicted by what form of photography you are going to do.
If you are going to shoot landscapes, you will need larger apertures in your image which will ensure that a major portion of the scenery is sharp and in focus whereas if you want to go for Macros and Portraits, you would need smaller apertures which will isolate your subject/model from the background and totally captures the attention of the viewer.
The best way to clear your concepts about Aperture is to take your camera and experiment. Take a series of shots with different apertures, from smallest to largest. You will have the hang of it in no time and can produce better pictures.
Image Credits: Ishan Pathak | Paul Robertson