50mm

The distance between the centre of the lens and the film, the focal length, ensures the object is accurately focused even when the subject is located quite far away. It is measured in millimetres (e.g. 50mm) and is marked on the camera mount along with the largest aperture for photographer’s convenience. A focal length of any given camera decides its category into normal, telephoto and wide angle. It is essential in photography as it establishes field of view of the camera, which is indirectly proportionate to the focal length. A normal lens that is compatible with 35 mm film with the focal length of 50mm, gives a field of view that is almost equivalent to that of normal vision of humans. A telephoto lens aids in magnifying the subject, albeit it narrows the field of vision, resulting in images with flatter looks compared to that produced by standard lens.

If one selects a good 50mm lens, it will give better results than other focal lengths, with reduced noise and distortion. It is the most commonly used lens and hence, is widely available. A 50mm lens has an ability to focus down to 17", while taking a close-up photograph. Besides, it also has a wide focusing range ñ infinity to life size. A 50mm lens is one of the standard lens used in photography and has formed the bases to calculate many photographical terms.