Depth Of Field in Photography
How does aperture control Depth Of Field
Aperture is one of the main controls in photography. As you know we can set our exposure by using Shutter speed, ISO, and Aperture. But controlling exposure is not the only important performance of the aperture. Another significant role is to control the Depth Of Field.
What is Depth Of Field?
I found the best description for depth of field in Wikipedia:
“In optics, particularly as it relates to film and photography, depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image. Although a lens can precisely focus at only one distance at a time, the decrease in sharpness is gradual on each side of the focused distance, so that within the DOF, the unsharpness is imperceptible under normal viewing conditions.
In some cases, it may be desirable to have the entire image sharp, and a large DOF is appropriate. In other cases, a small DOF may be more effective, emphasizing the subject while de-emphasizing the foreground and background.”
Although it may seem complicated, in real life application it is not. As a rule of thumb the higher f-stops (higher the number) give greater depth of field, with more of the scene appearing to be in focus in your photo. And vise versa, a lower f-stop results in a smaller (shallow) depth of field, with only one sharp and focused point in the image.
There are several other rules which apply to depth of field, such as lens focal length and the size of your media (sensor or film), which I will discuss in a different article.
For these photos the camera was on a tripod, ISO 200, Aperture Priority mode.
You see that as I opened up the aperture (set f-stop to a lowest number) the background and foreground go out of focus. It is a simple and effective technique to ensure your main subject is noticeable to viewers at the first glance.
On the other hand some time you want to keep everything in the scene in focus, then you need to use a value for aperture (f22 and higher)
If you want to learn more Register for our Understanding Exposure in Digital Photography workshop on May 22, and 23. Class size is limited.
Ted and Omnilargess Team