For a 35 mm camera, a telephoto lens has a focal length greater than the standard lens or about 58mm. This is also known as a long focal length lens. Years ago, long focal lenses basically had the lens located at the end of a long tube. Therefore, a 500mm lens was placed 500mm from the film, etc. By using other glass elements the light passing through the lens can now be modified, enabling the lens barrel to be shorter than the focal length of the lens. These lenses are designed to make distant objects appear larger. However, it's not the same as moving closer to your subject as telephoto lenses don't allow additional perspective distortion. Telephoto lenses are used from a greater distance to capture the same size image produced by shorter lenses at closer distances. Flatter perspectives are produced with further camera distances, but because the lenses magnify the subject, they retain normal size images. They also have less depth of field than shorter lenses.
Some examples of 35 mm camera telephoto lenses are 85 mm, 400 mm and 600 mm lenses. Lenses come in different apertures and in auto and manual focus models. Telephoto lenses can cost between about $75 to several thousand.