Kenko 2X converters

One problem with medium format cameras is the lack of independent lens makers found in 35 mm format. You are stuck with your camera brand lenses and accessories except when it comes to teleconverters. Teleconverters are used to increase the focal length of lenses by a factor of 1.4X or 2X. A 200 mm f-4 becomes a 280 mm f-5.6 with a 1.4X and a 400 mm f-8 with a 2X converter. The loss of sharpness is not as big a problem as in 35 mm since larger negatives and slides made with medium format camera produce much sharper results so a minor loss in quality will not be that noticeable. Most camera brand converters cost close to or higher than $1000. Kenko  (part of THK, Tokina, Hoya, Kenko) offers high quality 2X converters for most medium format cameras. It is very sharp and can be attached to most lenses. The Kenko is a multicoated , 6 element converter, and fully automatic. It is available in Pentax, Mamiya, and Hasselblad mounts for all formats. They cost between $250 to $400 depending on the type of format and camera. If you want to gain some extra reach with your lenses Kenko 2X converter will do a great job at much lower cost. See Tips for more information on teleconverters.