Lens Repair Recommendations

[mickjazz]

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Have an Elmar (type) clone that needs cleaning. It's a Japanese Showa Kogaku Letana 5cm f3.5 in M39.

 

Lens is quite rare from 1940. A collapsible like many others. The blades appear glued together by oil, making a non circular opening. I'm 99% sure that the non circular opening is *not* a design feature and the oil/grease is not allowing the blades to position properly.

 

The issue in cleaning is that while the Letana looks like an Elmar, Similar, Industar etc., it doesn't have for example the barrel or front rim screws. No ring in the front.

 

Not too many people could have worked on this lens. Without sending it to Kanto, I'd like to find someone in the US who can do it. I asked Youxin and he thinks that they have worked on a Letana.

 

Anybody else come to mind ?

 

One unusual thing about the lens that I've never seen on any M39 lens. The tube that extends from the lens to move the focus cam. The end is not square, normal to the lens axis but is contoured on the edge that meets the cam. Initially I thought it was damaged or modified but later found an ou online image of another lens with the same feature.

Edited August 1, 2018 by mickjazz

[jerzy]

It is really rare lens, there are not too many photos in the web, found only one (Anastigmat).

Looks identical to Elmar. if there is no scre on front rim this means that it is only screwed in. Have you tried to unscrew it slightly?

The inner brass optic mount could be screwed into barrel like it was in very early Elmars.

If there are light baffles remove them, most probably you will find retaining ring underneath, if yes, remove it. Then try to unscrew the front rim. Can you post some photos?

[jerzy]

....non circular opening means that some of the blades are not fixed on one end. Have you ever assembled blades on Elmar? Will be similar here, I can send you some photos early next week when I will be back at home

[mickjazz]

Thanks Jerzy. Will post images of the lens.

[willeica]

 I have a Topcor 5cm f 3.5 in LTM mount (11 O'Clock  infinity) on a Leotax from the mid 1950s. It has an aperture ring rather than a little 'nail breaker' slider as on the original Elmars. It may be related to or descended from the Letana. The aperture opening is not fully circular unless the lens is wide open. As Jerzy says, a few pictures of the Letana lens would help.

 

William

[mickjazz]

Here are images of the letana 5cm. There is what may be a barrel screw but does not look to have a way to remove it, like it's a pressed fit maybe. Also there's a screw into the barrel at the front underneath the front rim. Can't see a ring on the front.

 

You see the focus tube end contour. Also the rather unusual bevel side on the stop.

 

It has sn 10278. No idea what the first was, maybe 10,000. This was on a Special A supposedly +/- 150 made.

 

Finally the non circular opening; aperture setting 4.5

 

M

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[mickjazz]

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[willeica]

Looks like stuck blades alright. My Topcor lens has an aperture which is slight less than circular, but it does not look like this. I would not try to fix something like this myself as the blades may need to be taken apart and re-assembly could be quite a job. That focus tube end is certainly unusual. It begs the question of what type of camera/rangefinder cam it was intended to match with.

 

William

[mickjazz]

One last image. Ring in the back and looks like a baffle ala elmar etc.

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[mickjazz]

The cam on the Special A looks like any leica screw mount. Same location. I'd post images but it's getting serviced. Shutter etc. The rf window is orange tinted like the yellow window of leica ii's.

 

I have half dozen Leotax but nothing like this one.

[jerzy]

I have only smartphone with me now, so cannot see all details on your photos. But I believe that you identified both screws, the one fixing front rim and the second fixing inner lens tube. Strange is that the rim does not have a hole, so how to access the screw?

Strange is as well that the screw in the barrel does not have a slot. Is it maybe only pressed inside?

Very interesting, I would love to open the lens. But I presume that you are based in US, so this is not possible.

@William - arranging the blades is not so complicated, but may take time. A simple tool can shorten the time significantly. I can post some photos when back home.

[TomB_tx]

I have some Japanese Elmar copies, but not that one. My ‘50s Leotax models came with Tokyo Kogaku lenses, and the Elmar copies are very faithful and well made.

The screw under the front rim is normal Elmar construction to retain the front rim, but Most have a hole in the rim to allow access to the screw. The bottom edge of your rim shows marks from accessing the screw.

The “plug” on the barrel is standard location (in line with the rim screw) for a screw to retain the inner optical assembly. Can’t tell if the “plug”, a filed-off screw, rivet, or possibly a seal over a screw of tin or other soft metal.

Youxin has worked on many unusual Japanese lenses for me, including a later Leonon 50 f2 from a late Leotax, and a Tanaka Kogaku 50. He has succeeded on all and caused no damage.

[mickjazz]

Agree Tom. No question a different Elmar clone. I have not been able to find the lens design as compared to the Elmar.

 

Yeah I think Youxin is the guy to do it. He's cleaned lenses for me. I did have an 8 element that he was unable to clean completely with coating damage to the 2 center elements on either side of the diaphragm. He felt it was a parts lens.

 

I sent it to Kanto and they ground off the damage coating and decorated. Beautiful job but pricey.

 

Youxin should be able to fix this one. Mainly the aperture.

Edited August 2, 2018 by mickjazz

[mickjazz]

Update on lens repair

 

I did unfortunately opt to send the letana with the aperture issue to Ye Camera.

 

He looked at it, don't know if he dismantled it didn't say in email note.

 

Said blades damaged, no repair possible. Send $15 for shipping. So I'm out $40 et shipping with nothing to show for it. I'm hoping they didn't break the blades.

 

 

That's or for me with Ye Camera. They have actually never repaired one of my lenses.

I understand his wife was doing the cleaning of lenses somebody told me. So 5 out of 5. And all were repaired by other folks including an 8 element 35mm that had 'uncleanable' haze between the 2 center elements. And was a junk 'parts lens'. That one I sent to Kanto expecting $500+ to grind off the coating and recoating. They cleaned it no problem.

 

I will not be doing any more business with Ye Camera. They are responsive but it seems they can possibly clean (some) lenses but repairs likely impossible.

 

No chance having them work on the Leotax Special A that came with the lens. I'll take both with me to Kanto in January.