Lenses are always identified by their focal length. It’s not just a physical measurement, it’s an indication of the type of lens it is, for example, a wideangle lens, standard lens, telephoto and so on. In other words, the focal length of the lens gives you an indication of its angle of view. Or at […]
A 'crop' sensor is one that's smaller than a full frame sensor. This means that it captures a smaller area and a narrower angle of view with the same focal length lens. In effect, smaller sensors make lenses look as if they have a 'longer' focal length, and by a specific factor – or 'crop factor'.