Photography Technicalities: Aperture

Photography is the art of capturing images on a camera. Photography is the science of capturing images on a camera. Both statements are tree of this unique art form. There are many different techniques that can be used throughout the process to achieve the photograph you want. However, it is important to know how the science of photography works in order to help you obtain your results. Finding the right aperture is in important piece of the equation.

Aperture is the measure of the diameter of the hole, or the input pupil, in the lens that lets light get to the film or sensor. It is determined by dividing the length of the lens (f) by the diameter of the pupil (D). It is usually noted by "f/" followed by a number (such as f/8); the higher the number, the smaller the diameter.

The biggest reason for changing the aperture on the camera is for setting the depth of field. Depth of field, often referred to as DoF, is a term used to describe the amount of a photograph that is in focus. A photo with a just the subject in focus and a blurry background, like in macro photography is considered to have a low DoF. This is created by having a lower f-stop number (like f1.4). A photography where everything looks to be in focus, like a landscape, is considered to have a high DoF. This is created by having a higher f-stop number (like f22).

Aperture affects exposure by changing the amount of light that hits the sensor. When you change the aperture, it also affects the shutter speed and the ISO settings. It is important that all three get adjusted depending on what the effect you are trying to get for your photograph. If you change the aperture to modify the depth of field, you need to change the shutter speed and ISO depending on the amount of light need for proper exposure. You need to keep this in mind when you are changing you aperture to fit your DoF needs.

Using aperture can help to really make a subject pop in you photograph. It allows you to make sure that certain parts of your photograph are in focus, and keeps your attention on the subject. Due to the change in diameter of the pupil, the aperture also affects the way that light hits the film or sensor. When changing the aperture, make sure that you are also changing the other elements that affect exposure. When used correctly, aperture can make unique portraits, but it is just another part of photography that mixes art and science.