A smaller sensor gives a more magnified image because it captures a smaller area of the lens. These sensors need lower comparative focal lengths to match the look of a full-frame image. On APS-C, the focal length of the lens can be multiplied by 1.5 to reach what is called its “equivalent focal length”, while Micro Four Thirds lenses must be doubled (via B&H Photo Video Audio). So if you want a 50mm look on a crop sensor, a 35mm lens should be used, or 25mm on Micro Four Thirds.
Once you have your focal length and aperture specs together, you can figure out what kind of lens you have, panasonic Remarks. For example, a 70-200mm f/2.8 lens will be able to zoom from 70 to 200 millimeters, with a minimum F-stop of 2.8. Lenses may offer additional features, such as close-up macro focusing or built-in image stabilization.
Photography Life points out that you need to know what lens mount your camera body uses, as almost every company has a specific type. Mirrorless cameras can also have completely different mounts than their DSLR counterparts from the same manufacturer. Perhaps the most versatile mount is the NikonF, found on SLR cameras dating back to 1959. With the purchase of adapters, most lenses can be adapted to cameras from other companies, but functions such as autofocus may lose compatibility. It’s easier to stick to one brand.