A standard lens is a photographic lens with a focal length approximately equal to the diagonal of the film or digital sensor format it is designed for. This focal length produces a field of view that closely resembles what the human eye naturally sees, resulting in images that appear neither compressed nor exaggerated in perspective.
Standard lenses are often considered versatile and ideal for general-purpose photography, including portraits, street photography, and everyday scenes. Because they offer a natural perspective and minimal distortion, they are frequently the first lens photographers choose for their cameras. Their simplicity, combined with optical quality, makes standard lenses an essential part of a photographer’s kit, especially when an accurate and lifelike representation of the subject is desired.