Types of Lenses for DSLR

The ability to change lenses adds versatility to a camera. There are many lenses (called "glass" by professionals) available for digital single-lens reflex, or DSLR, cameras to transform ordinary snapshots into professional-quality images.

Basic Lenses

If the DSLR is purchased in a "kit', meaning that there is a lens with it, the lens will probably be a versatile 18mm to 55mm lens. This is the standard lens with about 3X zoom. Other basic lenses are 18mm to 70mm, 18 to 135mm and 18 to 200mm. The higher the second number (focal length), the more powerful the zoom capability. There is also an 'f' number (representing the maximum aperture) which shows the lens' speed or light sensitivity. Lower numbers, such as f2.8, let in more light.

Telephoto and Supertelephoto Lenses

Telephoto lenses bring distant objects closer in nature, sports and other applications.Telephoto lenses can also be used for more flattering portraits of humans. Super telephoto lenses, with focal lengths higher than 500mm, can be more than a foot long. They are heavy and attach directly to the tripod for better balance. These are the lenses seen on the sidelines of professional sports contests and at birdwatching events, for example.

Fixed-Focal-Length Lenses

Also known as prime lenses, fixed-focal-length lenses are made to be used at only one focal length. These can be more compact and have larger maximum apertures (lower 'f' numbers). These are useful for photographers who are generally the same distance from their subjects, as with fashion, entertainment or sports photography.

Wide-Angle Lenses

Wide-angle lenses are used to get more of a scene into an image, as with broad landscapes or a situation where you can't back up (a room). The wide-angle lens can also emphasize the foreground or alternate perspective (from below or above subject). The focal length of a wide-angle lens is usually 12mm to 24mm.

Macro Lenses

Macros allows objects only a couple of inches from the lens to be photographed for extreme close-ups. This technique is commonly used for flowers and insects. Because of the macro's extremely shallow depth of field, it can capture some petals of a flower in focus and blur others.

Specialty Lenses

Fish-eye lenses bend the lines in a photo around the center. Ultraviolet lenses are used for scientific applications. The Lensbaby company makes three lenses (Composer, Muse and Control Freak) that allow for selective focus. This technique is especially effective in close-ups, because the photographer can blur the edges of a photo right up to the subject.

References

• David Pogue's Digital Photography; David Pogue; 2009
• The Digital Photography Book; Scott Kelby; 2007

Resources

• Lensbaby