Archived posting to the Leica Users Group, 2007/06/23

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Subject: [Leica] 'cron 50mm DR on M8
From: kididdoc at cox.net (Steve Barbour)
Date: Sat Jun 23 15:30:46 2007
References: <5.1.0.14.2.20070623000603.00bdbb40@mail.2alpha.com> <B93CAC88-A478-4FC6-9575-C95ACA46B9C3@btinternet.com> <AA23CB5C-1D58-4A6A-AC3E-F207B8F1AC87@cox.net> <8FD3092E-2050-4AE2-BD48-5765208481B7@btinternet.com> <02165062-CB1F-4BB3-BEB9-8BE70067226E@cox.net> <D4F300C1-640A-49AC-9966-B5FAB7B2EF1E@comcast.net> <DD000D8B-BC54-4D1F-A88B-FBCF13A76BE7@cox.net> <9b678e0706231516o143b2cb9nebb8b0bc5fb70477@mail.gmail.com>

thanks Don...that is remarkably lucid, and helps a lot. Steve


On Jun 23, 2007, at 3:16 PM, Don Dory wrote:

> Steve,
> The DR and the "Rigid" Summicron are probably the same formula: we  
> have had
> many a long discussion about this over the years.  It is a seven  
> element
> formulation which is very different from the current formula.  In  
> essence,
> the DR is the last of the high resolution relatively low accutance  
> designs.
> The next formulation went for much higher contrast/accutance at the  
> expense
> of some resolution.
>
> The confusion comes about because MTF charts are all about the  
> ability to
> define square wave forms so the new designs are created for the  
> test.  Older
> designs would resolve much higher resolutions at admittedly low  
> contrast.
> Think of a really long tail where even at very low contrast levels  
> you can
> distinguish between two lines.
>
> On 6/23/07, Steve Barbour <kididdoc@cox.net> wrote:
>>
>>
>> On Jun 23, 2007, at 12:26 PM, Leonard Taupier wrote:
>>
>> > Steve,
>> >
>> > The experts say the DR and the Rigid made at the same time ( 1956 -
>> > 1968 ) are the same lens in formula and performance.
>>
>>
>> so I have one further question and we can wrap this up....
>>
>> are they in fact the same optically as the current !!  summicron
>> 50/2  and if not, how are they different...
>>
>>
>> and yes I have read Puts and Gandy, and each time they seem more
>> confusing, Steve
>>
>>
>> >
>> > Len
>> >
>> >
>> > On Jun 23, 2007, at 3:20 PM, Steve Barbour wrote:
>> >
>> >> sorry Frank...
>> >>
>> >>
>> >> this discussion is getting a little too deep for me...  :-)
>> >>
>> >>
>> >> is the cron 50 DR identical to the old rigid cron 50... of that
>> >> era...
>> >>
>> >>
>> >> or is it identical to the cron 50 which is available today  ?...
>> >>
>> >>
>> >> (as people say that the two are different from one another)
>> >>
>> >>
>> >>
>> >> thanks, Steve
>> >>
>> >>
>> >> On Jun 23, 2007, at 12:11 PM, Frank Dernie wrote:
>> >>
>> >>> I mean contemporary with the one you own.
>> >>> Frank
>> >>>
>> >>> On 23 Jun, 2007, at 13:49, Steve Barbour wrote:
>> >>>
>> >>>>
>> >>>> On Jun 23, 2007, at 12:49 AM, Frank Dernie wrote:
>> >>>>
>> >>>>> The contemporary
>> >>>>
>> >>>>
>> >>>> thanks Frank... do you mean the contemporary from then or
>> >>>> now....  ?
>> >>>>
>> >>>>
>> >>>> Steve
>> >>>>
>> >>>>
>> >>>>> rigid Summicron is identical to the DR, apart from the close
>> >>>>> focus arrangement. If you like the look so much why not get one
>> >>>>> of those as well?
>> >>>>> Frank
>> >>>>>
>> >>>>> On 23 Jun, 2007, at 08:29, Peter Klein wrote:
>> >>>>>
>> >>>>>> Steve:  That was me.  I had the idea of getting a cheap Rigid
>> >>>>>> Summicron with bad glass and the correct focal length marked
>> >>>>>> inside.  The DR and Rigid lens heads unscrew from the mounts,
>> >>>>>> so I thought I could put my DR lens head in the rigid mount
>> >>>>>> for the M8, and still have the close range on film.  I asked
>> >>>>>> DAG about it, and he said that the mounts were different and
>> >>>>>> it wouldn't work.  But he also said that he could cut off the
>> >>>>>> close focus part of the cam, and then it would work in the
>> >>>>>> normal range on the M8.
>> >>>>>>
>> >>>>>> The unmodified DR does work in close-focus range on the M8.  I
>> >>>>>> know for sure, because I've tried it. When it's set in the
>> >>>>>> normal range, the close-focus half of the cam sticks out too
>> >>>>>> far, and it hits something inside the body when you try to
>> >>>>>> mount it.  I have read about this, and I have decided to
>> >>>>>> believe it and not try it myself.  :-)
>> >>>>>>
>> >>>>>> I'm still thinking about whether to have DAG do the
>> >>>>>> "operation."  It will depend on how much I like the 67mm
>> >>>>>> equivalent length the 50mm turns into on the M8.  And whether
>> >>>>>> I want to desecrate a sacred object.   Funny that I feel this
>> >>>>>> way--I've used the close range all of twice since I got the
>> >>>>>> lens.  But another DR was my first Leica lens, way back in
>> >>>>>> 1970.  I really love how the DR draws, how it's made, how it
>> >>>>>> feels.  And it's a Wetzlar product from the Golden Age.  So
>> >>>>>> I'm reluctant to give the lens a "vasectomy" unless I'd really
>> >>>>>> use it a lot on the M8.
>> >>>>>>
>> >>>>>> Decision postponed while I experiment with my other 50s.
>> >>>>>>
>> >>>>>> --Peter
>> >>>>>>
>> >>>>>> At 02:29 PM 6/21/2007 -0700, Steve Barbour wrote:
>> >>>>>>>  recall hearing that the cron 50mm DR can be modified,
>> >>>>>>> so that it can be used on the M8 body...
>> >>>>>>> maybe that was reported here...
>> >>>>>>> if someone can substantiate this, and give me details, I'd
>> >>>>>>> appreciate
>> >>>>>>> it...
>> >>>>>>>
>> >>>>>>> thanks, Steve
>> >>>>>>
>> >>>>>>
>> >>>>>> _______________________________________________
>> >>>>>> 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
>> >>>>
>> >>>>
>> >>>> _______________________________________________
>> >>>> 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
>> >>
>> >>
>> >> _______________________________________________
>> >> 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
>>
>>
>> _______________________________________________
>> Leica Users Group.
>> See http://leica-users.org/mailman/listinfo/lug for more information
>>
>
>
>
> -- 
> Don
> don.dory@gmail.com
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information


In reply to: Message from pklein at 2alpha.net (Peter Klein) ([Leica] 'cron 50mm DR on M8)
Message from Frank.Dernie at btinternet.com (Frank Dernie) ([Leica] 'cron 50mm DR on M8)
Message from kididdoc at cox.net (Steve Barbour) ([Leica] 'cron 50mm DR on M8)
Message from Frank.Dernie at btinternet.com (Frank Dernie) ([Leica] 'cron 50mm DR on M8)
Message from kididdoc at cox.net (Steve Barbour) ([Leica] 'cron 50mm DR on M8)
Message from len-1 at comcast.net (Leonard Taupier) ([Leica] 'cron 50mm DR on M8)
Message from kididdoc at cox.net (Steve Barbour) ([Leica] 'cron 50mm DR on M8)
Message from don.dory at gmail.com (Don Dory) ([Leica] 'cron 50mm DR on M8)