The Samyang 8mm f/2.8 UMC Fisheye Lens is a high quality ultra wide angle lens designed exclusively for the Sony NEX (E-mount) and Samsung NX compact system cameras. It gives an immense field of view - 180 degrees, with a 12 mm (35 mm equivalent) field of view. The 8 mm is a diagonal fisheye lens for APS-C format, meaning that the image it produces fills the frame on APS-C cameras. As with all current Samyang lenses it is manual focus only. It is also compact, and lightweight, giving a perfect combination with Sony NEX and Samsung NX compact system cameras. The optical construction of the lens is 10 elements in 8 optical groups including one aspherical and two ED elements for optimum optical performance. The aperture consists of six diaphragm blades with apertures available from f/2.8 to f/22. It has an internal focusing (IF) system which means the lens does not change in size when focusing. Additionally, the Samyang 8 mm fisheye features the latest generation multilayer anti-reflection ultra multi-coating (UMC) to minimize flare and ghosting. The integrated lens hood also helps to reduce flare from behind the lens. Due to the very large depth of field produced by such a small focal length lens, focus can be easily achieved by simply setting the approximate distance on the lens scale. Setting the lens to around 1 m at f8 will produce images that are sharp from very close objects to infinity. As with all manual focus lenses for critical or in very close focus situations you can use live-view to fine-tune the focus manually.