Telephoto Lens Facts
Sometimes good photography subjects, such as hot air balloons or hang gliders, are too far away to capture on film. At those times, telephoto lenses are the best solution. A telephoto lens has a narrow angle of view, a very long focal length (normal focal length is about 50mm), and can magnify images across long distances, making them excellent for wildlife and nature photography and candid shots.
History
History typically credits Thomas Rudolphus Dallmeyer as the inventor of the photographic telephoto lens in 1891, but other people also invented them during the same time period.
Function
Telephoto lenses function much like telescopes by narrowing the scene and bringing subjects closer into view.
Focal Length
On a 35mm camera, a telephoto lens will have a focal length of 85mm or more.
Elements
A telephoto lens consists of front lens elements with a positive focus, and rear lens elements, or a telephoto group, with a negative focus.
Warning
"Camera shake" can be a problem when using a telephoto lens. When the focal length is long, it's harder to keep the lens steady.
Fun Fact
As of October, 2006, the world's largest non-military telephoto lens is made by Zeiss and has a focal length of 1700mm.
Tags: focal length, telephoto lens, telephoto lens, focal length, lens elements
