MFT cameras are physically slimmer than most interchangeable lens cameras because the standard specifies a much reduced lens mount flange to imaging sensor plane distance of just . Typically this so-called flange focal distance is over on most interchangeable lens cameras. The MFT system design flange focal length distance allows for, through use of an adapter, the possibility to mount virtually any manufacturer's existing and legacy still camera interchangeable lens (as well as some video and cine lenses) to an MFT body, albeit using manual focus and manual aperture control. For example, many theoretically obsolete 35mm film camera lenses, as well as existing current lenses for APS-C and full frame DSLR's are now usable on MFT cameras. As an example, an older (i.e., used, obsolete and low priced), but still high quality, 50mm f/1.8 "standard" lens from a 35mm film camera can be used on a MFT camera body. With MFT sensors having a crop factor of 2.0, the old 50mm f/1.8 "standard" lens becomes a high-speed (although manual) 100mm f/1.8 telephoto portrait lens. So the MFT system allows the re-use of expensive lenses that may have outlived their 35mm film format camera, and can be used on a modern digital camera body capable of both still and HD video recording. Similarly, the MFT system design allows current DSLR lenses to be used as well, although only with manual focus and aperture control.