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Serenar 100mm F4 on a IIIB body


ralf_j.

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Hello all -

 

I got my first Leica, a IIIB a couple of weeks ago and have basically no

experience with it in using a short telefoto lens. The closest experience I

have had to a Leica type camera, has been the using of a couple of Russian

clones, however the were only used with their standard 50mm lenses.

 

I picked up a CANON Serenar 100mm F/4 and my question is regarding the range

finder. Does the rangefinder focus in the same fashion as it would on a

standard 50mm lens? I am having trouble alignig the images in the rangefinder

at the correct distances altogether. Is there any specific thing I am doing

wrong during mounting the lens or anything else?

 

This lens focuses down to 3.5 feet according to its scale, however the images

on the rangefinder do not align where they should at 6 feet of a distance, it

looks like it comes pretty close to the infinity mark.

 

Any help on this would be greatly appreciated.

 

Thank you

 

Ralf

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Does your camera focus ok with another lens?

 

Sounds like your rangefinder maybe out of alignment. Unless you are handy with fixing

these mechanical cameras, I'd suggest you send your IIIB (and the Canon) to a reputable

repair person and have it checked. A CLA would be a good idea for these older cameras

anyway.

 

Did you purchase the items with any guarantees?

 

RT

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hmm,

 

Does the lens mount correctly, is the focus mark arriving at about 2 o'clock when viewed from the front?

 

You could try mounting the lens whilst its at its closest focus to make sure the rangefinder coupling cam is not binding during mounting...

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Most, if not all, rangefinder lenses other than 50mm have a possibility to adjust the rangefinder coupling cam/ring.

 

But first check whether your lens has a coupling ring (a ring protruding from the lens mount which moves in and out as you focus) or a tab. In the latter case it might be possible that the tab does not hit the cam follower on the camera body properly since there is no precise stop of the lens mount.

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It's quite possible that some unskilled repair person put the lens together wrong, with the focusing helical on the wrong start of the threads. Also, there's a screw in many such long-focus LTM rangefinder lenses that can adjust the rangefinder coulping cam.

 

As Ben noted, the lens should mount with the focus mark somewhere between 12 and 2 O'clock on the front of the camera. The rangefinder coupling cam needs to be in a position where it pushes on the roller inside the camera. If it doesn't, either the lens mount is rotated on the camera, or perhaps there's a mis-assembly of the mount to the lens.

 

The other check is to see that when the lens is focused at infinity (off camera) that the rangefinder cam projects back from the flat mating surface of the lens mount exactly 7.5 millimeters. If it doesn't, the lens is not assembled right.

 

The rangefinder cam should also move into the lens as you focus it closer. If you focus the 100/4 and your 50mm lens to the same distance (on the scale), the cam should stick out the same distance on both lenses. It is possible that the lube grease on the rangefinder cam is ossified, and it isn't sliding into the lens correctly. It should ride against a rather curved surface on the rear of the focusing helical visible inside the lens, but the spring that does this isn't very strong.

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John, there's probably something holding up the focusing cam. Dirt, a burr, something like that. I don't have the Canon 100/4, so I can't comment on the exact construction, but I suspect that the mount is pretty much a direct copy of the Elmar 90/4, even if the optics aren't.

 

I do have the Canon 135/4 and 135/3.5, and both use the same cam design, where it is spring loaded against a very curved cam on the rear of the focusing helical. Focus your 100/4 to 1 meter, and push on the focus cam -- I suspect it will lurch further into the lens.

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Thank you for your answers. I brought it to the repair man and it appears the problem was with the threaded mount on the camera body. The lens' focus indicator would not go past 11 o'clock. He replaced it and all is well now. Once again thank you for taking your time to respond to this post.
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Also - this is an image i took with my serenar 100 f/4(didn't have the appropriate viefinder so the framing is way off), but it appears my leica is leaking light :-(. Do you think this is caused by a damage to the curtain as the leak appears like a central streak? Here is a sample.<div>00O9Q7-41257384.jpg.f04ed80a65e12c97602032ce025de7b6.jpg</div>
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This was a 24 exposure roll and and about 70% of it was shot with a Jupiter-8 and the rest with the serenar 100mm F/4. The light leaks are apparent on all the frames. I am inclined to think about pin holes on the curtains but it is hard to check with a bottom loading camera.
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I (fortunately) do not have any experience with pin holes on curtain shutters but I think these should show up in a different way. I have severe doubts whether light streaks caused by pin holes will show up 90 deg. to the direction of travel.

 

I rather think that there are some light leaks around the back of the camera.

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I (fortunately) do not have any experience with pin holes on curtain shutters but I think these should show up in a different way. I have severe doubts whether light streaks caused by pin holes will show up 90 deg. to the direction of travel.

 

I rather think that there are some light leaks around the back of the camera.

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