This example illustrates the difference in opening size in the iris of a lens at different F-stops. Notice that the smaller numbered F-stop is actually the larger opening of the iris.
What Is Aperture?
With photography it's all about the light and your camera sensors ability to get the right amount of it, for the appropriate length of time.
The lens is the part of the camera used to collect and control the amount of light allowed inside. Aperture, in combination with shutter speed, regulates the degree of light allowed into your camera's sensor.
The aperture is the opening of the lens, or the hole (diaphragm) in which light travels through to the sensor of the camera. A diaphragm in the lens acts much like the iris of an eye, controlling the diameter in which the lens opens. The larger the diameter of the aperture, the more light that will reach the camera's sensor.
Aperture is weighed in small increments know as F stops, (F1.8 up to F22) The smaller the F stop number or value, the larger the lens opening, or aperture. For example F2.8 would allow the iris of the lens to open to a larger size and therefore allow more light into the camera sensor. F16 on the other hand will open the lens only slightly, resulting in less light into the camera.
So a smaller F stop value means a larger lens opening or larger aperture, and a larger F stop value means a smaller lens opening.
But how does that effect the actual image produced?
Aperture will effect the exposure of your image. If you are in a low light situation a larger aperture (lower f stop value) would produce and better exposed image since the larger lens opening will allow more light into the camera.
In contrast, a sunny day might prompt you to lower the aperture (higher F stop value), restricting light into the camera and saving your image from the certain doom of over exposure.
Notice that all objects in the photo, both near and far are clear and in focus. Photo: Gila Todd
Aperture also effects the depth of field in your images or how much of your image, at varied distances, will be in focus.
Notice only the face of the subject is in focus. Photo: Gila Todd
Notice only the face of the subject is in focus. Photo: Gila Todd
Aperture is but one variable in the process of exposing an image. Read future articles here about what those variables are and how they work in unison to form a technically correct photograph.
Happy Snappin!
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All text in this article is © Gila Todd , unless otherwise indicated. Available for reprint and/or publishing only with written permission from author. Contact Gila with your comments, suggestions, questions, and ideas.
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