Archived posting to the Leica Users Group, 2008/12/09

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Subject: [Leica] M-lenses on M8
From: kididdoc at cox.net (Steve Barbour)
Date: Tue Dec 9 15:43:03 2008
References: <5.1.0.14.2.20081208222311.02812ea0@mail.threshinc.com><B5475F98-2020-4290-816F-3C88015CD60F@cox.net><a3f189160812090843i10363186kd197e8b13487ef77@mail.gmail.com><2208E56B-F253-43B2-8338-02300D7CF128@cox.net> <F5338B3BF5A14A0AB433ADBD80E39B27@D1S9FY41> <85991F6E72EA47EE92DD554C4E557D7D@D1S9FY41>

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
>>
>>
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In reply to: Message from pklein at threshinc.com (Peter Klein) ([Leica] M-lenses on M8)
Message from kididdoc at cox.net (Steve Barbour) ([Leica] M-lenses on M8)
Message from sonc.hegr at gmail.com (Sonny Carter) ([Leica] M-lenses on M8)
Message from kididdoc at cox.net (Steve Barbour) ([Leica] M-lenses on M8)
Message from sethrosner at nycap.rr.com (Seth Rosner) ([Leica] M-lenses on M8)
Message from sethrosner at nycap.rr.com (Seth Rosner) ([Leica] M-lenses on M8)