Digital Photography 1A Practice Test

A telephoto lens typically decreases the depth of field when compared to wide-angle lenses. This effect occurs due to a combination of focal length and the distance from the subject. As the focal length of the lens increases, the plane of focus becomes narrower, resulting in a more pronounced separation between the subject and the background.

In practical terms, this means that objects that are not in the focal plane will be out of focus to a greater extent, making the subject stand out sharply against a blurred background, which is often desirable in portrait photography or wildlife photography. This characteristic makes telephoto lenses particularly effective for isolating subjects and creating a more professional look in images.

While other variables such as aperture and sensor size play a role in determining depth of field, the inherent qualities of a telephoto lens primarily lead to a decrease in depth of field, allowing photographers to achieve specific artistic effects in their work.