90mm f4 Elmar varients on Bellows II and focal depth / 3 Element questions

[kdt]

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I have both a 1950 LTM and 1960 M version of the 90mm f4 Elmar. I primarily use them head only on my Bellows II with 16558 adapter . Both lens heads can be focused to infinity on the Bellows II but the LTM version requires the bellows to be focused closer to the film plane lens to get infinity than the M lens on the Bellows II . The lens flange to film plane distance is shorter with the LTM

The lens heads can be interchanged between the regular LTM and M focusing helicoids but they are not comparable with the infinity setting due to the different lens flange to film plane distance. I purchased a OUAGO Visoflex helicoid with the hope of using it with both LTM and M heads but the LTM lens head will also not focus to infinity. Only the 1960 version works at infinity. 

1) I am interested in purchasing a three element version 90mm Elmar. Can anyone tell me if the 3 element lens can focus to infinity on the bellows II with 16558 adapter?

2) Does the OUAGO visoflex helicoid focus to infinity with the 3 element Elmar?

Thanks!

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[UliWer]

The lens head of the 1:4/90mm Elmar with three elements will focus with the OUAGO or the Bellows II with 16558 to infinity - if you use either a Visoflex body or something which substitutes the Visoflex on an M.

 

[UliWer]

vor 3 Stunden schrieb kdt:

The lens flange to film plane distance is shorter with the LTM

I fear you misunderstand something: LTM-Leicas have a longer flange to film plane distance than M-Leicas. Therefore you add an LTM-to-M-adapter which prolongs the camera’s flange to film distance if you use an LTM lens on an M. 

If you don‘t use the lens directly on the camera‘s body but add a Visoflex housing this housing will cope for the differences: a Visoflex for LTM has a thinner flange than an M-Visoflex.  So in any case a lens head together with a helicoid to be used on a Visoflex should work the same way. Remember that the OUAGO was introduced at a time when most lenses were for LTM; there were no two different OUAGOS for LTM and M lenses. My OUAGO - together with a Visoflex III - works as well for the head of an LTM 90mm Elmar as for one with M bayonet. 

Edited July 12, 2024 by UliWer

[kdt]

If I understand correctly all 90mm f4 Elmars use the same flange depth from the perspective of the head on its own and should all work with the OUAGO with Visoflex II and III... Until purchasing the OUAGO I have only used this early LTM lens on the bellows II on which it is easy to hide a collimation issue.  The resolution seems to be ok but it is possible it has been improperly disassembled and needs to be re collimated. These lenses are so easy to take apart I am sure many have been serviced incorrectly.

Edited July 13, 2024 by kdt

[UliWer]

vor 8 Stunden schrieb kdt:

If I understand correctly all 90mm f4 Elmars use the same flange depth from the perspective of the head on its own and should all work with the OUAGO with Visoflex II and III... Until purchasing the OUAGO I have only used this early LTM lens…

How „early“ is your 90mm lens head?

Looking deeper into the Forum one finds the following explanation:

When I tried my lens heads 165.xxx and 962.000 I found out that neither would focus to infinity. I never realized this before as I never used them on the Visoflex for anything at infinity; the proper lens with shaft on the camera will serve this purpose better. 

[kdt]

When I tried my lens heads 165.xxx and 962.000 I found out that neither would focus to infinity. I never realized this before as I never used them on the Visoflex for anything at infinity; the proper lens with shaft on the camera will serve this purpose better. 

 

This is interesting... and a much more probable reason for the focus issue. My LTM 90mm is from 1950 serial #807xxx. Using the 1950 lens head on the 1960  Std. M mount has the same issue of not focusing to infinity ... As I do not have a thread to M adapter I have not tried this lens mount on a camera. I am away from home for the weekend and will measure the two standard mounts and post the measurement difference when I get back. I will check the thickness of a LTM to M adapter and add this to the measurement. My guess is the std. LTM mount will be longer.

My 1950 and 1960 lens heads are considerably different. The 1950 version has different optical elements and the size of the head is much smaller and lighter than the 1960 E39 version. The 1950 is much more like the pre war lenses I have seen. Perhaps mechanical changes were needed in certain years due to optical glass availability

This whole issue is not really a problem for me as my preference is to use these lenses with the bellows II. I found a mint OUAGO at a reasonable cost and could not resist. It was the surprise that this issue existed and thought an answer would follow on this website.

Many thanks for the links about this... It is something to consider for purchasers of these old lenses to know the limitations of the different versions ...

 

Edited July 13, 2024 by kdt

[UliWer]

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I think the reason for the incompatibility of older lens heads with the OUAGO is the lens head's flange:

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The flanges of the two older lenses (left 165.xxx and middle 962.000) are "higher" than for the 3-element's head (right) not leaving enough space for the head to screw into the OUAGO. So their position is too much protruded to reach infinity. 

[01af]

vor 2 Stunden schrieb UliWer:

[...]

The flanges of the two older lenses (left 165.xxx and middle 962.000) are "higher" than for the 3-element's head (right) ... 

Umm ... but you are aware that in order to see any differences in the lens heads' flange distances, you'd have to align their rear principal planes, not their filter threads' front rims, aren't you?

Edited July 14, 2024 by 01af

[spydrxx]

My 1955 LTM 90/4 Elmar, 1285749, focusses to infinity on both the 16558 (Z) /bellows/Visoflex combination as wells as on the Ouago/Visoflex combination, In fact it actually focuses at infinity slightly before the end of its travel on the Ouago. I should mention I'm speaking of optical infinity, not the moon, as it has been cloudy and rainy several nights in a row so I couldn't validate a better target, but rather objects 300 yards away. According to Uliwer's comparison photo of the three versions, mine appears to be the middle one. Sorry I can't help with the 3 element question (I'm not sure what serial numbers used 3  elements...is that the one on the far right in he picture?).

[kdt]

Great to see the comparison of the 3 heads in the photo that UliWer posted. My 1960 M lens would fit between the right hand two in UliWer's photo... I agree that the measurements need to be made from the bottom on the lens head flange that would mate with the OUAGO.or standard focus mount. My feeling is that leitz changed the length of the standard focus mount. The lens heads would  collimate differently as a result. Why they would do this is unclear. I will do some measurements when I return home on Tuesday to confirm this. .

Does anyone have an LTM to M adapter and could measure the thickness with a caliper? I'm having difficulty finding the flange to film plane distance for LTM and M cameras.

Edited July 14, 2024 by kdt

[spydrxx]

My Leica 90mm LTM-> M adapter thickness measures 0.96mm, measured with a digital caliper. My Voigtlander one measures 0.95mm. Several other generic ones of mine measure 0.95-0.96m.  My old notes of published flange depth of LTM and M bodies are as follows: Leica M mount = 27.8mm Inner rails, 27.95mm outer rails: Leica LTM mount = 28.8mm. Hope this helps.

[UliWer]

The LTM-to-M-adapter from Leitz/Leica is supposed to be 1mm thick - if you measure it with a caliper it is less thick. Being screwed onto an LTM lens it will substitute the 1 mm which the lens needs. 

The flange-to-film distance of a Leica LTM is 28.8mm, for a Leica M it is 27.8mm. 

[kdt]

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I found this image while looking for information on the 3 element lens. Assuming that all of these lenses are focused to infinity it is surprising to see how the length of the LTM lenses vary. The M rear caps are a bit thicker than LTM so hard to compare. I would question if #6 would work with a OUAGO to infinity. Edited July 14, 2024 by kdt

[UliWer]

I wouldn't bother too much about the shaft's length or the overall length of the lenses. Much more important is the position of the lens head's exit pupil. As I tried to show in #7 the older lens heads could not be screwed in as much as the later version. So the fixed dimension of the OUAGO couldn't cope for all lens heads.

[kdt]

1 hour ago, UliWer said:

I wouldn't bother too much about the shaft's length or the overall length of the lenses. Much more important is the position of the lens head's exit pupil. As I tried to show in #7 the older lens heads could not be screwed in as much as the later version. So the fixed dimension of the OUAGO couldn't cope for all lens heads.

This could be the issue...Measurements  will be interesting

[UliWer]

vor 8 Stunden schrieb kdt:

Measurements  will be interesting

May be - though you don‘t know much if you learn that there are differences.

Looking at the lower flange (the upper one in my photo in #7) shows that the older lens heads cannot be screwed in as much as the newer one which hasn’t got this flange. That makes the difference for the OUAGO.

[01af]

vor 18 Stunden schrieb kdt:

... the measurements need to be made from the bottom on the lens head flange ...

No.

.

vor 10 Stunden schrieb UliWer:

Much more important is the position of the lens head's exit pupil.

No.

As I already said, the important thing is the position of the lens head's rear principal plane. Unfortunately, you cannot figure it out by simply looking at the lens. You'd have to take a look at the lens' constructional drawing—which usually isn't available to us users. You could measure the position—but in order to do that, you'd need to know the exact focal length. 90 mm is just the nominal value; the exact value could be anything between, say, 87 and 93 mm.

[kdt]

It will be easy to find the difference through measurement. We have a known distance with the mount that will focus the lens to infinity. I have four possible ways of mounting the 1950 lens heads.

1) With standard LTM helicoid mount plus LTM to M adapter

2) With standard helicoid M mount **

3) With OUGAO and Visoflex II or III **

4) With the  bellows II and 16558 adapter

Each of these options allow the use of all 90mm lens heads. ** Two of my options will not focus to infinity with the 1950 head. It is my guess that the difference between where the 1950 lens and the 1960 lens focus to infinity is around 6 mm I will measure both LTM and M standard mounts accurately on Tuesday. The LTM mount should be 7mm shorter than the standard M mount. (1 mm added for LTM to M adapter).  I will measure from flange to flange not just height.

A lens collimator would be the ideal option but a caliper will point to the difference close enough.

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[UliWer]

You might try the following:

When you screw off the lens head and look into the shaft of your lens you may find some scratched in writing:

Here the shaft of an Elmar from 1952:

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The four digits "2068" are the last digits of the lens head's serial number; this indicates that the shaft belongs to the head.  Then there is a "90" at the left which you might read as "96" though I think it really stands for "90" meaning the actual focal length. The letters are not clear, they may stand for the people who made the measurements and/or controlled them.

Here you have a shaft of a very early Elmar:

This is clearly "90" - meaning the actual focal length. I don't find any other scratched-in writing.

The shaft of a 3-element Elmar only has the three last digits of the lens head scratched inside the shaft. Though this lens has the "magic digits" officially engraved at the shaft's outside on the focussing scale at the right side of the "m" for meter. These "magic digits" say "00" - which stands for 90.0mm. I am not sure if there are late versions of the 4-elements Elmar with M-mount which also show the two digits engraved on the outside. LTM lenses never have them, they were introduced in the late 50s though perhaps not for all lens types. My collapsible Elmar with M-mount from the mid-50s doesn't have them.

P.S.: here you may see a late 4-elements Elmar with M mount (approx. from 1961) which shows the engraving "00" for 90mm.

https://www.ebay.de/itm/355074806730?itmmeta=01J2XJT541B5H9C47V824PX555&hash=item52ac1b93ca:g:tFQAAOSwcQJlGjDW&itmprp=enc%3AAQAJAAAA4Ma4T%2Bn4p8azf7%2BVmPmZ5MygWguyelalpav3nrCFkVkTOv%2B0ipzGAkJ7bSPiHY6rvZSlwp5mJYjKjTOzLlWznIwhrXnGP3C4fL7BFNhNQq69M37jXh9ovXNRPWYoGlpOZshav%2F763zOkSyQPhh2nOhSVa7xQ1LFutOvtPfRNvkxTmx%2F%2B3r0N6rybXrIKEMutPVneVuZuTFVkyOnGsSFaOMJBrEu3wMdWIBMUSol4pIwyUt9ASe%2FrYjX%2BbnEKENfQbG4hwdmVVv3tuzYWSpYIGUZSW814HlybEzFtQRYrQIsy|tkp%3ABk9SR47S6LKXZA

 

 

Edited July 16, 2024 by UliWer

[kdt]

Looking at the two standard 1950 and 1960 focus mounts (LTM and M) I measured from the bottom of the male flange that mounts the lens into the camera body to the female end top flange where the lens head screws into it.

1) LTM focus mount is 50.5mm + 1mm for the LTM to M adapter= 51.5mm

2) M focus mount is 53.9mm

There is 2.4mm difference in the optical center of these two lens heads in relation to the flange on the bottom of lens heads. This prevents the older lens heads from focusing to infinity with the OUAGO. There is sufficient extra room on the bellows II/16558 adapter to focus to infinity with the older lens head but the 90mm ruled scale on the bellows is 2.4mm off.

So I assume that the pre war and many LTM pre M mount 90mm f4 Elmar lenses use this shorter length of focus mount and will have this issue with the OUAGO...*** What about the LTM 3 element 90mm f4 Elmar?  Are they all compatible or are the LTM 3 element 90's an issue

Edited July 16, 2024 by kdt