carl Carl Zeiss Flektogon f/2.8 20mm MC PL-MOUNT LENS ARRIFLEX ARRI RED ONE 35MM Written by admin on December 19th, 2023. What really sets the 20mm Flektogon apart from other super wide angle lenses is not only the close focusing distance but also that it is a relatively sharp lens at f2.8. This makes it suitable for available light photography in most cases.