Pentax 200mm F/4 SMC A K-Mount Manual Focus Lens {52}

A lens is considered telephoto if it magnifies the image by a factor of about 1.5x. This is based on 35mm full-frame or digital full-frame sensors. For example, a 100mm lens for full frame 35mm used on a digital camera with a sensor size such as APS-C format, will become a 150mm equivalent to 35mm full-frame. The smaller the sensor, the greater the ratio will be. If this is used with 35mm or full-frame digital, with a 100mm lens, you will double the magnification of a 50mm lens. This range and 80mm range are perfect for portraits, as they reproduce the human face without distortion. For example, using a 50mm or normal range will make the face slightly larger than normal and a 135mm lens would make the face more narrow than normal. The telephoto range of lenses can be 85mm, 135mm, 180mm and 200mm.