OUAGO & 90mm Elmar - question for experts

[spydrxx]

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I recently picked up a 90mm f/4 Elmar #1285xxx which works just fine on all of my LTM and M bodies. When reading thru previous posts on the forum, I noticed that some models in a particular numeric production range, such as mine, were annotated as needing to be sent to the factory for adjustment to use on a OUAGO/Visoflex combination. I'm assuming this means to achieve infinity focus, but since I don't have an OUAGO at present to test it out, I was wondering if anybody out there knew what this adjustment consisted of. I did see one earlier post which suggested the pitch of the threads of the lens head might be different among the variations of the lens. Not a big issue for me as I do have a 90mm f/2.8 Elmarit which I use on my Visoflex, but I was mostly curious about what the issue is with this particular model. Thanks in advance.

[luigi bertolotti]

That's a tricky question... the pitch of the thread mount of the lenshead, in itself, is the same for all the Elmars 90.... I can mount the head of my E39 1.3xx.xxx on the focus mount of my prewar 3xx.xxx (it's the same thread even in the 3 slements 90, too it mountable on OUAGO/OTQNO, though you cannot mount its lenshead on former Elmar 90 mounts).

So... I tend to think that is a matter of shim(s) to be inserted at the base of the thread... but I have not any evidence of this (and...I confess that I haven't tried all my Elmars 90 heads on OUAGO + Viso to verify focus at infinity... ) Also Jim Lager, in his book on lenses, does report that "some of the old Elmars 90" needed "adjustment" to achieve infinity focus on OUAGO...

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[gyoung]

Old Leica catalogues also have this reservation, and indeed my 90/4 does not focus quite to infinity on a viso 2 with OUAGO. I'm sure there is a serial no mentioned in the catalogue (1960s) but I am away from home now and dontt have the 90 or the catalogue.

 

Gerry

[luigi bertolotti]

Gerry... you gave a right suggestion which didn't come to my mind... but I am so lucky to be at home with 1961 catalog : speaking of the OUAGO (16467N) they say :

 

"lenses above 1.572.401 can be used readily with 16467N"

"lenses from 697.901 to 1.572.400 require adjustment at the works"

"lenses under 697.901 can be used with 16467N but not up to infinity"

 

And both those "threshold" s/n belong to batches of Elmar 90, obviously.

What is the nature of the "adjustment" they don't detail... difficult to think it's a work/substitution of optical elements... I keep my idea on shimming (or, more probably, vice-versa.... filing/lathing(*)).; unluckily, all my (seven... ) Elmars 90 are under 1.572.401 (apart the 3 elements) and can't make any visual comparision or measure...

 

(*) By logic, if the issue is infinity focusing, lens group must penetrate a bit MORE into the OUAGO mount... which could be accomplished by an expert mechanical, working on the thread with a lathe machine... of course this would impact also the usage of lenshead on its std. focusing mount, so probably the factory adjustment involves also it...

About the fact that very old lenses (< 697.901) apparently can't be adjusted, I have noticed that the lenshead construction of my 321.867 is indeed slightly different from more recent items... indeed it seems to me that to work on the "new" threads is quite easy , while on the "old" one, looking at the alloys used, looks a more difficult or even impossible work.

 

Another strategy of adjustment could be a slight repositioning of the whole lens' assembly into the head... maybe easier, with shims... of course, also this would require an adjustement of the focusing mount.

Edited November 17, 2014 by luigi bertolotti

[k-hawinkler]

Thanks Luigi.

 

I have several OUAGOs, an Elmar 1.355.xxx, and a 3-Element Elmar 2.124.xxx.

Interesting, so my 3-Element Elmar 2.124.xxx should work fine with the OUAGO.

But the Elmar 1.355.xxx "would require adjustment at the works".

Do you think Leica does still do that? TIA. If not I could ask DAG about this.

 

A couple observations.

The lens head of the 3-Element Elmar seems a smidgen taller.

It fits, however it doesn't screw as deeply into the OUAGO as my other lens head.

[luigi bertolotti]

Thanks Luigi.

 

I have several OUAGOs, an Elmar 1.355.xxx, and a 3-Element Elmar 2.124.xxx.

Interesting, so my 3-Element Elmar 2.124.xxx should work fine with the OUAGO.

But the Elmar 1.355.xxx "would require adjustment at the works".

Do you think Leica does still do that? TIA. If not I could ask DAG about this.

 

A couple observations.

The lens head of the 3-Element Elmar seems a smidgen taller.

It fits, however it doesn't screw as deeply into the OUAGO as my other lens head.

 

It seems difficult, in my opinion, that Leica still can work at that level on old Elmars 90... after all, Visoflex and its complex bunch of accessories is a system that iirc, was put out of production more than 30 years ago... your idea about DAG is probably the best one... they are traditionally "deep into Viso" and probably , about this tricky question on lensheads, do know much more than us (I suppose there must be some precoius service docs of the era in the hands of labs like DAG... )

Btw (waiting for more tests at home when have time... ) the 3 elements is my only Elmar of which I am directly SURE that works at infinity on OUAGO... I remember well to have used it (alone and with the OTQNO, too) on my M4+VisoII years ago..

[k-hawinkler]

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http://www.l-camera-forum.com/leica-forum/leica-m8-forum/353897-visoflex-question.html#post2821581

[spydrxx]

K.H. Thanks for the link, but I definitely wasn't contemplating puting the whole thing on the Visoflex, but rather possibly using the removable lens head on a OUAGO (short focusing mount). It was the issue of "factory adjustment" which I was questioning.

[gyoung]

With mine (ser no 719...) I decided that it was unlikely that 'the works' would do it for free (!) and the cost of it would comfortably exceed the amount I paid for the lens. If I want infinity on a visoflex (or my FM2 and Fotodiox viso to Nikon F adapter) I have a 90/2.8 Elmarit I can use

 

Gerry

[spydrxx]

UPDATE. My OUAGO arrived today and I mounted the lens head, so that satisfied me that the issue wasn't a screw pitch issue. I initially put it on an adapter on my micro 4/3 body and it focused fine at infinity as well as close in. I then mounted it on a Visoflex and was mildly surprised that it not only focused at infinity, but went a little beyond (as some telephotos do to accommodate thermal expansion). So I'm a happy camper. I now think maybe the factory adjustment may be merely to shim so that infinity is at least achieved and that close focusing is within tolerance of the stated range.

[Nordvik]

My 1937 lens head will only focus to 3,5 meters. The treads go about 0,7mm too deep. I can not see any easy fix for this.

[jc_braconi]

My 1937 lens head will only focus to 3,5 meters. The treads go about 0,7mm too deep. I can not see any easy fix for this.

 

May be a washer 0.7mm thickness