The Rokinon 8mm t3.8 AS IF MC CSII DH Cine Fisheye Lens for Micro Four Thirds Mount offers features designed for shooting HD video that differentiate it from "photo lenses." Its click less aperture ring is not only silent but enables continuous smooth transitions between stops. Aperture is marked in T-stops (Transmission-Stops) which represents a more accurate measurement of the light that actually makes it all the way through the lens and provides a more consistent measurement when comparing lenses. Additional "Cine" features include geared aperture and focus rings to enable the use of apparatus such as a follow focus system. On an Olympus or Panasonic MFT format camera, its 35mm focal length equivalency is 16mm that can focus down to 12 inches and cover the entire frame with the desirable perspective that only it's extremely wide 139 degree angle of view can deliver.. Aspherical lens elements and UMC multi-layer coating combine for sharp, high-contrast imaging and its redesigned hood can now be easily removed if desired.