Archived posting to the Leica Users Group, 2000/09/15
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]It would seem to me to Leica's advantage to make LTM as their default mount. Is there any image quality lost when using an LTM version with an adapter as compared to the M mount version of the same lens? By making LTM lenses default (sold with an M adapter standard), Leica might encourage a few budget minded folks to use classic or new C/V LTM bodies instead of buying an M body first, but they would also make their lenses more adaptable and desirable to a broader market without lessening their dedication to their current M clients or costing themselves huge amounts in retooling. If anyone sees a flaw in this logic please point it out. Carpe Luminem, Michael E. Berube At 09:33 AM 9/15/00 -0600, John Collier wrote: >A rangefinder lens requires a focusing cam to couple with the camera's >rangefinder. The camera's rangefinder is designed to couple correctly to the >natural focus movement of a 50mm lens. All other focal lengths require a >compensating mechanism to: increase the focusing cam's movement as compared >to the wide angle lens' natural focusing movement; or, decrease the focusing >cam's movement as compared to the long lens' natural focusing movement. If >you are making an SLR lens into a rangefinder this will require designing a >completely new focusing mount. As rangefinder cameras constitute a limited >market, production numbers are fairly low. The Pentax "limited" production >run of 2000 may well take many years to sell out. > >The problem with converting M lenses to LTM is that the M lenses were >designed to be physically longer so that you could mount the shorter LTM >lens on to a M camera using an adapter. You cannot just unscrew the M mount >and screw on a LTM mount, the rear of the lens has to have 1mm machined off. >That is not much but Leica has not been in the habit of designing in extra >space just in case! So, again, a new focusing mount has to be designed and, >again, demand will be low. > > The new mount designs required and low production runs mean higher costs. >The Cosina/Voitlander lenses are often touted as low cost but that is only >compared to Leica prices not regular SLR prices. Except, of course, in the >super wide angles where you can design an uncoupled rangefinder lens to be >much less expensive to produce than a complicated mirror clearing retrofocus >SLR design. > >John Collier