Camera lenses come in either fixed (prime, fixed lens camera) focal lengths, or zooms, which cover a range of focal lengths. The different focal lengths are grouped into categories for different types of camera lenses.
Traditionally, a super wide-angle lens is classified as anything under 20mm. Wide-angle is 21-35mm. With the advent of digital cameras, and the APS-C format, camera manufacturers have also started producing specific lenses for this format. Wide-angle lenses for crop frame DSLRs range from 10-24mm, with a few going down to a super wide 8mm.
Wide-angle lenses are most commonly used for photographing landscapes and architecture, although they are often also used for photographing large groups of people.
The Canon EF-S 10-18mm f/4.5-5.6 is an example of a wide-angle lens (10-18mm).
A standard lens has a focal length range of 35-70mm. The most common standard lens is a fixed 50mm lens.
Standard lenses are most commonly used for documentary and street photography, where photographers need to move quickly and capture an interesting point of action. Pioneers of modern street photography, such as Henri Cartier-Bresson, always used a 50mm lens, choosing to move themselves around so as to best frame an image.
The Nikon 50mm f1.8D lens (pictured here) is an example of a standard, fixed lens.
The focal range between 80-135mm is nearly always used by portrait photographers. Fixed lenses at these lengths produce ideal framing for head and shoulders shots. These are specialist lenses, but can be surprisingly reasonably priced.
The Canon EF 100mm F/2.8 Macro USM lens is an example of a one of these types of lenses.
Any lens with a focal length of between 135mm and 300mm is a true telephoto lens. Manufacturers make a huge range of lenses in this range ... at an equally large range of prices!
Telephoto lenses are traditionally used for sports and wildlife photography, but their essential function is to bring distant objects closer.
One example of a telephoto lens is the Canon EF-S 18-200mm f/3.5-5.6 IS USM telephoto lens pictured here.
There are a variety of specialist camera lens types available. Some of the more common are:
- Super Telephoto. These have a focal length of more than 300mm, and are used by dedicated sports and wildlife photographers. The Nikon AF-S Nikkor 400mm f/2.8G super telephoto lens (pictured here) is an example.
- Macro. These lenses are able to focus closer to an object than normal lenses, offering a 1:1 ratio. They are used for still-life photography of small objects.
- Fisheye. These are on the edge of wide-angle lenses, and give a distorted view of the subject matter. The center of the image is magnified, and objects diminish in size in all directions around it.