Archived posting to the Leica Users Group, 2000/08/18
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> Brougham asked > > > What about some of the retrofocus designs for the M6 to accomodate the > meter? Are they "less" retrofocus than the corresponding designs to > avoid the mirror path? > > Yes there is. Some 50s are retrofocus on SLRs, the shorter the focal length the more retrofocus the lens must be to clear the mirror. A 15mm lens to clear the mirror is huge and very retrofocus, the 15 Voightlander is slightly retrofocus, small and cheap despite being excellent. The new 12mm Voightlander may not even be economically feasible in SLR mount. There is one benefit to retrofocus. The Cos ^4 light falloff rule is reduced the more retrofocus the lens is, however all other parameters of optical and geometrical correction worsen as the lens gets more retrofocus. cheers Frank