Close-Up and Macro Photography Sensors in DSLRs with a "crop factor" of 1.5× or 1.6× are often given the generic name of APS-C (referring to the size of the APS film system), but there are several variants between manufacturers. Effect of Sensor Size on Focal Length Lenses can generally be divided into the broad categories of standard, wide- angle, and telephoto. The standard-length lens gives an angle of view similar to that of the human eye when viewing a scene in a fairly relaxed mode, without straining peripheral vision. With 35 mm film and digital cameras, the standard focal length of the lens is 50 mm, derived from the approximate length of the diagonal across the 24 × 36-mm film/sensor area. Wide-angle lenses have focal lengths shorter than 50 mm (e.g., 28 or 35 mm), while telephoto lenses have focal lengths longer than 50 mm (e.g., 100 or 200 mm). Where a camera has a sensor smaller than 35 mm, the length of the diagonal