Understanding Camera Lenses

Camera lenses are an important element of photography because they control how light is directed to the camera's film or digital sensor. Different lenses can make faraway objects look close up or make a single subject remain in focus while blurring the background.

Types of Zoom

Lenses can have a fixed focal length, known as a prime lens, or encompass multiple focal lengths, known as a zoom lens. Zoom lenses allow the photographer to recompose the picture without moving, but prime lenses provide slightly better quality.

Aperture

How much light a camera lens lets in is denoted by the aperture. The smaller the number, the more light the lens lets in. Lenses with apertures of 2.8 or less are known as "fast" lenses and are used for capturing high-speed action.

Focal Length

Focal length represents the camera's angle of view. The angle of view of a human eye is 40 mm to 60 mm. Lenses with focal lengths longer than that will decrease the field of view but enlarge subjects that are farther away.

Focus Type

Some lenses only have manual focus. Others add an automatic focus option. A relatively new option is full-time manual, which relies on the camera to set the focus but allows the photographer to adjust it without changing the settings or damaging the lens.

Lens Quality

Lens of a higher quality will generally carry a higher price tag. These lenses will have special features such as image stabilization or ultrasonic motors.

References

• Camera Lens Characteristics