How to Buy a Lens.

The article presents information on the features of the lens of digital single-lens reflex (DSLR) camera. A lens's focal length, represented in millimeters, is the distance between the rear element of the lens and the focal plane, where the parallel beams of light entering a lens converge to a point. The focal length determines the lens's viewing angle, the shorter the focal length, the wider the field of view, and the more of a scene a camera can capture. The aperture is one of the mechanisms that control the amount of light that passes through the lens to the image sensor. The speed of a lens is described by its maximum aperture. The lens included with many DSLR kits takes one from a moderate wide-angle view to a slight telephoto.