Micro 4/3, also referred to as MFT, is a standard for digital mirrorless interchangeable-lens camera systems. This system was created by Olympus and Panasonic. The name '4/3' refers to the aspect ratio and size of the image sensor, which is smaller than APS-C or full-frame sensors used in other cameras. The absence of a mirror mechanism, typical for digital single-lens reflex (DSLR) cameras, allows for the construction of smaller and lighter camera bodies and lenses. Thanks to the smaller sensor, lenses for this system have a 'crop factor' of 2. In practice, this means that the focal length of the lens is multiplied by two to determine the real angle of view; for example, a 25mm lens will provide the same field of view as a 50mm lens on a full-frame camera. As it is an open standard, other companies can also manufacture lenses and cameras for this system, ensuring a wide range of compatible accessories.