Archived posting to the Leica Users Group, 2011/03/13

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Subject: [Leica] M9 and DR 'Cron
From: photo.forrest at earthlink.net (Philip Forrest)
Date: Mon, 14 Mar 2011 00:36:56 -0400
References: <mailman.973.1300073659.1011.lug@leica-users.org> <4D7D9389.7040909@verizon.net>

The DR Summicron can only be used in close-focus range with the M8 and
M9. It must be mounted to the camera in this range and not moved to the
1m-infinity normal range. The close focus cam on the back of the
helicoid will contact the body of the camera at all distances in the
normal range. If you work hard enough at it, you could pull the camera
apart with that very fine piece of leverage built into the lens.

I solved this problem by using the optical head of the DR on a 51.9mm
calibrated helicoid for a rigid summicron of similar vintage. The
optics were removable for use on a Visoflex but it also allowed for the
exchange of optical units between the DR and rigid summicrons. Beware
though, the DR 'crons were all calibrated to a 51.9mm nominal focal
length and only some of the rigid 'crons were. I happened to get lucky.
most of the rigid summicrons are 51.6mm even though the optical unit
will interchange nicely. Mixing them up will result in a focus error
throughout the focusing range but it will be most evident up close and
probably about imperceptible near infinity.

I finally got sick of using the optics on both helicoids and recently
purchased another rigid summicron as I don't want to cut down my close
focus helicoid on my DR.

Phil Forrest



On Mon, 14 Mar 2011 00:03:21 -0400
Stan Yoder <s.yoder at verizon.net> wrote:

> Someone please refresh my (aging) memory re: the problem with this 
> combination. Some kind of mechanical interference, right?
> 
> TIA,
> Stan Yoder
> 
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information



In reply to: Message from s.yoder at verizon.net (Stan Yoder) ([Leica] M9 and DR 'Cron)