What are telephoto lenses?
Lenses with a focal length longer than that of a 50mm standard lens can be classed as telephotos. In practice though, 85mm is regarded as the shortest telephoto focal length for fixed or prime lenses, while for telephoto zoom lenses, the short end of the telephoto range starts around 70mm, as in a Canon 70-200mm telephoto zoom. Telephoto Lens Magnification The longer the focal length of a lens, the greater the magnification. Thus a 100mm telephoto lens gives twice the magnification of a 50mm standard lens. In practice, this means the subjects height and width in the viewfinder and hence on the digital sensor or film – is doubled when you attach a 100mm lens to the camera. Similarly, a 400mm telephoto lens gives eight times (x8) the magnification of a standard lens. If youre on safari and theres a big male lion staring at you from 50m away, hes going to appear very small in the viewfinder with a 50mm lens on the camera. Change that to a 500mm telephoto lens, and the lion is magnified 10
