What is a telephoto lens?

A telephoto lens is a photographic lens with a longer focal length than a standard lens. Its viewing angle is less than 20 degrees, and its focal length can reach tens or hundreds of millimeters. Telefocal lenses are divided into ordinary telephoto lenses and ultra-telephoto lenses. The focal length of ordinary telephoto lens is close to that of standard lens, while the focal length of ultra telephoto lens is much larger than that of standard lens. Take 135 camera as an example, the photographic lens with a focal length of 85 mm-300 mm is a normal telephoto lens, and the lens with a focal length of more than 300 mm is a super telephoto lens.

A telephoto lens has a long focal length, a small viewing angle and a large image on the negative. Therefore, at the same distance, you can take larger images than the standard lens. Suitable for shooting distant objects. Because its depth of field is smaller than the standard lens, it can blur the background more effectively and highlight the focused subject, and the subject is generally far away from the camera, which makes the portrait more realistic in perspective, so people often call the telephoto lens a portrait lens. The telephoto lens is often used in professional photography because of its long lens barrel, heavy weight, relatively expensive price and small depth of field, and it is difficult to focus in practical use.

When shooting with a long focal length lens, you should generally use a high sensitivity and a fast shutter. For example, when shooting with a 200mm long focal length lens, the shutter speed should be above 1/250 seconds to prevent camera shake when shooting with a hand-held camera. In general, in order to keep the camera stable, it is best to fix the camera on a tripod. Try to find something to help stabilize the camera without a tripod.