Archived posting to the Leica Users Group, 1999/02/10

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Subject: Re: [Leica] Using 2 cam lenses on an R3
From: "Robert G. Stevens" <robsteve@istar.ca>
Date: Wed, 10 Feb 1999 18:02:43 -0400

Alex and Dan:

I noticed a  problem trying to use an R to M mount adapter.  One of my
lenses would not mount and I figured out the difference.  There are two
different Leica bayonets with a difference in the machining.  If you look
at the mating surface on the lens side, some are machined all the way under
the bayontet lugs and others stop just underneath the lugs and there is a
step.  On the newer camera side flanges, they have a larger opening to them
to allow this raised portion to fit.  It may allow for a tighter
registration of the lens to the camera.

I placed a 35mm Summicron which does not have the step and a macro adapter
extension tube on my scanner to show the differences.

http://home.iSTAR.ca/~robsteve/photography/images/bayonet.jpg

I would assume your 50mm has this little step up on the lens flange and the
SL has the different style flange.

Perhaps the more knowlegeable on the LUG can explain why this change was made.


Regards,

Robert


 At 07:23 PM 2/10/99 +0000, you wrote:
>Dan Post wrote:
>>I have the same model 50 Summicron, three cams with built in lens shade, and
>>have no problem using it on my SL!
>>Is it possbile there might be some damage there?
>
>The lens flange looks perfect, and the mounts on the SL bodies show very
>little wear. It just seems a bit reluctant to fit in the throats of either
>of my SLs. Just tried again, and it definitely doesn't go on either.
>
>I obviously don't want to force it. The strange thing is that all the SL
>lenses mount very sweetly on the R3. I can't believe that Leitz got their
>flange tolerances wrong. Just to add to the mystery, the R lens _does_
>mount OK on the front end my 2x Extender R, the back end of which is
>specifically for Leicaflexes.
>
>S/N of this strange reluctant Canadian 50/2 Summicron R is 2824064. This
>wouldn't be one of the rare R  beasts where the mount is purposesly
>designed so it _can't_ be mounted on 'flexes? I seem to recall reading
>something about that somewhere, but it would only make sense for 3rd
>cam-only  lenses - whereas this is definitely 3-cam.
>
>BTW, I may have the solution to my own question about using 2 cams on R
>cameras. How about:
>
>1) Select a suitable shutter speed in manual mode.
>
>2) Stop-down the lens using the DOF preview lever until the meter needle
>coincides with the shutter speed selected.
>
>3) Release DOF lever and shoot.
>
>I don't think it can be used in program mode because that would require the
>3rd cam to transmit the aperture information while the lens remains wide
>open.
>
>Could someone out there confirm this or correct me?
>
>TIA
>
>Slan
>
>Alex
>
>Alex Hurst
>Waterfall
>Nr. Cork
>Ireland
>
>Tel: +353 21 543 328 (H)
>       +353 21 270 907 (W)
>
>Fax: +353 21 271 248
>email: corkflor@iol.ie
>Home website: http://homepages.iol.ie/~corkflor/
>Business website: http://www.flowerlink.com/corkflorists
>
>
>
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