Lens Elements and Image Quality

The camera component referred to as a “lens” is actually made up of several different lens elements. Each of these elements plays a role in directing light rays through the camera onto the film plane or digital sensor with a minimum of optical aberrations. Blurring, vignetting, distortion, loss of contrast, and chromatic aberration are all possible aberrations that reduce image quality. Although all lenses will have optical aberrations to some degree, higher-quality lenses will have fewer, less noticeable optical aberrations, resulting in an image that is truer to life.

Focal Length
A lens’s focal length determines its angle of view, and, as a result, how much of a subject it will be able to capture from a single vantage point. Wide-angle lenses have short focal lengths, while telephoto lenses have longer focal lengths. Along with maximum aperture, focal length is one of the two fundamental parameters of an optical lens. The result of focal length in an image is the amount that perspective seems to be stretched. For example, a wide-angle lens with a short focal length makes objects in the distance seem to be farther away, while a telephoto lens with a long focal length makes distant objects seem closer. The following table shows the terminology that goes with several ranges of focal lengths and which subjects are most appropriate for each type.