There are a few general ranges of lens lengths, with multiple options throughout each range. Wide angle lenses capture the whole scene, normal lenses are similar to what your eye sees, and telephoto lenses get you in close.

Wide Angle Lenses

Wide angle lenses fall into the range of 16mm to 35mm.

A wide angle lens is one that captures a sweeping view of what's in front of you. Rather than zooming in, a wide angle zooms out and captures your subject in its environment.

Wide Angle Effects

Wide angle lenses not only take in a wider view, they also stretch it out. Things that are far away (such as distant mountains) will appear even further away. Wide angle lenses provide a large depth of field, which means that objects both near and far are more likely to be in focus.

The wider they get, wide angle lenses begin to produce a great amount of distortion. From 24-35mm, the distortion is noticeable but not disconcerting. From 20mm on down to the fisheye level, distortion, especially on the sides and corners of an image, becomes readily apparent. Making sure your camera is level can help reduce some types of perspective distortion. And keeping your subjects at the same distance helps as well, as closer objects will appear much bigger than those in the background.

Normal Lenses

Normal lenses fall into the range of 35-70mm

A normal lens, especially a 50mm, replicates the focal characteristics of the human eye. This makes it a good starting point for beginning photographers. You can learn about depth of field and composition without also having to learn the effects of different focal lengths. Others would say that normal lenses are just that, normal. But in the hands of a good photographer, the normal lens is just as effective a tool as any.

Telephoto Lenses

Telephoto lenses cover the range of 70mm to 600mm.

These are the lenses that get you in close. There are many photographic situations where you simply can't get close to your subjects, sports being the prime example. A telephoto lens magnifies the scene, bringing your subject right up to the frame. Telephoto lenses are also the largest and heaviest lenses.

Telephoto Effects

Where a wide angle lens pushes everything back a telephoto lens brings everything close, compressing the scene. The mountains that shrink in the background of your wide angle shot will be brought in even closer than normal with a telephoto.

Also compressed in a telephoto lens is your depth of field. The range of focus becomes very tight, resulting in blurred foregrounds and backgrounds. This selective focus look is often a hallmark of professional photography.

With telephoto lenses, you'll pay more for magnification and speed. Analyze your needs. If you're shooting sports such as football or soccer, a 300mm or 400mm is typical. If you're shooting wildlife, you might be looking at a 500 or a 600mm. But don't forget you may be able to save a lot of money through buying a shorter lens and equipping it with a teleconverter.