Kenko 400mm f/8 Mirror Lens

Kenko Tokina has announced the upcoming release of the new Kenko 400mm f8 mirror lens for Micro Four Thirds and Sony’s NEX system. Being only 112mm in length, the Kenko 400mm f8 is rather compact for a super-telephoto lens. Like the majority of existing mirror lenses, this is a manual-focus lens with a fixed aperture and a machined aluminium barrel. The Kenko 400mm f/8 takes 67mm filters, and can focus down to 1.15m, at which point it offers an impressive reproduction ratio of 1:2.5. The lens will be released in Japan this Thursday.
The company also offers the lens in Canon EF, Nikon F and Pentax K mounts. The SLR version of the Kenko 400mm f/8 lens is, interestingly, even smaller than the CSC variant, being only 82mm in length. It also differs from the MFT and Sony versions in having an all-black finish.
Source: Kenko Tokina