In photography, a telephoto lens is a lens. There are two different uses of the word. The less specific use is to mean a lens that has a longer focal length than a normal lens. Their angle of view is smaller than that of a normal lens. With telephoto lenses things look closer than they really are.
The other meaning of telephoto lens applies to lenses that are constructed in a special way so they can be shorter than their focal length.
For 35 mm film, 50 mm is a normal focal length. Typical telephoto lenses are 85 mm (28°50') and 100 mm (24°). They are used for portraits mostly. Other telephoto lenses that are used often are 135 mm (18°), 180 mm and 200 mm. Many are zoom lenses.
Longer focal lengths (300 to 1200 mm) are used in sports and nature photography.
Different focal lengthsEdit
Effect of different focal lengths on photographs taken from the same place: