Archived posting to the Leica Users Group, 2008/12/09
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]On Dec 9, 2008, at 2:21 PM, Seth Rosner wrote: > P.S. I should have added to my earlier post on using the optical > unit of a rigid 50 Summicron on a DR focus mount; the exact focal > length of the DR, every DR, is 51,9mm, i.e. the focus mount is > calculated for a focal length of 51,9; whereas the Rigids can come > in a few different exact focal lengths, 51,9mm and others, e.g. > 51,3mm etc (I'm not sure what the exact other focal lengths are). > You can tell the exact focal length of a particular example of > either DR or Rigid, it will be inscribed by hand on the black back > retainer ring of the optical unit and visible when the unit is > dismounted; on the Rigid but not the DR, the last two digits of the > exact focal length are also engraved to the right of the rangefinder > scale on the focus mount, i.e. for a lens focal length of 51,9mm > will be engraved '19'; for focal length 51,3 will be engraved '13' > etc. Obviously a DR (focal length 51,9) optical unit will not focus > accurately on a Rigid focus mount engraved anything other than '19'. yes, thanks Seth...I knew this, likely from your own previous dialogue some years ago.. exactly as you say, I looked for a rigid mount and only considered those of the 19 type, of those some were thread wise OK, some were not... Steve > > > ----- Original Message ----- From: "Seth Rosner" <sethrosner@nycap.rr.com > > > To: "Leica Users Group" <lug@leica-users.org> > Sent: Tuesday, December 09, 2008 2:24 PM > Subject: Re: [Leica] M-lenses on M8 > > >> Steve - and Sonny - take care; the only issue there is that the >> threads of >> the Rigid Summicron focusing mount do not uniformly match the >> threads of a >> particular optical unit. Some years ago, thinking to use the >> optical unit of >> my DR as a rigid, I bought a focus mount from Don Goldberg who >> warned me >> about this and offered to take it back if it didn't work. It >> didn't. Result >> was that the optical unit, when mounted on the adapter and my M4 or >> M6 had >> the diaphragm and rangefinder scales completely out of sight, a bit >> to the >> right of bottom dead center. So a focusing mount might, or might >> not, match >> and align the optical head correctly. >> >> Best, >> >> Seth >> >> ----- Original Message ----- From: "Steve Barbour" <kididdoc@cox.net> >> To: "Leica Users Group" <lug@leica-users.org> >> Sent: Tuesday, December 09, 2008 11:57 AM >> Subject: Re: [Leica] M-lenses on M8 >> >> >>> >>> On Dec 9, 2008, at 9:43 AM, Sonny Carter wrote: >>> >>>> On Tue, Dec 9, 2008 at 8:45 AM, Steve Barbour <kididdoc@cox.net> >>>> wrote: >>>> >>>>> >>>>> and I know you are a DR guy... >>>>> >>>>> I did as Peter did...the DR on the M8, nice.... >>>> >>>> >>>> Mine is up there too, getting surgery >>> >>> you'll like it Sonny, call it a DiRcumcision... >>> >>> a bit drastic at its age, but worth it. >>> >>> The other way to go is to remove the DR lens cassette, screw it >>> into a >>> matched Summicron Rigid body/M adapter, >>> >>> >>> Steve >>> >>> >>> >>>> >>>> >>>> -- >>>> Regards, >>>> >>>> Sonny >>>> http://www.sonc.com >>>> http://sonc.stumbleupon.com/ >>>> Natchitoches, Louisiana >>>> USA >>>> >>>> _______________________________________________ >>>> Leica Users Group. >>>> See http://leica-users.org/mailman/listinfo/lug for more >>>> information >>> >>> >>> _______________________________________________ >>> Leica Users Group. >>> See http://leica-users.org/mailman/listinfo/lug for more information >> >> >> -------------------------------------------------------------------------------- >> >> >> >> No virus found in this incoming message. >> Checked by AVG - http://www.avg.com >> Version: 8.0.176 / Virus Database: 270.9.15/1839 - Release Date: >> 12/9/2008 >> 9:59 AM >> >> >> _______________________________________________ >> Leica Users Group. >> See http://leica-users.org/mailman/listinfo/lug for more information > > > -------------------------------------------------------------------------------- > > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.176 / Virus Database: 270.9.15/1839 - Release Date: > 12/9/2008 9:59 AM > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information