What's a telephoto lens and why should you choose one?

A telephoto lens is a zoom lens that allows you to get far away subjects closer. Telephoto lenses have a focal length somewhere between 70mm up to 600mm. The focal length is simply the distance between the sensor and the center of the lens in millimeters. The larger this distance, the closer you can get to the image. A lens is called a wide-angle lens if it has a focal length of 24mm or smaller. It's a telephoto lens if it has at least a 70mm focal length.

Telephoto lenses are available with a wide range of focal lengths. A variable focal length is common in telephoto lenses. This means that you can determine how close you get to the subject. With a 70-300mm lens, 70mm means you're already zoomed in on the image and 300mm will bring you really close to the subject. With a large zoom range, you run the risk of motion blur. The more expensive models have image stabilization to tackle this problem. Photographers whose pockets are less deep can use a tripod.

You choose a telephoto lens if you can't get closer to your object but still want to photograph it. If you like to take photos of nature, a telephoto lens is a good choice. You can capture a deer from afar when you see one during a hike, for example. You won't have to get up close and scare off the animal. Telephoto lenses are often used for sports photography too. You can take impressive photos from the sideline.