old Elmarit 90f2.8 1960s front focus on M8

[chounws]

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Hi,

May be someone can give me an advise would be very appreciate.

Just got this old 1960s lens Elmarit 90f2.8 from Korea, and found that at all distance no matter close to infinity the focus will always at front of the focusing point I did aim.

After read some of the posts I think the distance of the Viso lens element with the film (sensor) plane need adjustment. But I'm not so sure where to trim it down.

Please see the picture below.

Any advise thank you very much

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[jaapv]

Judging by the numbers scratched in, the lens and the barrel were correctly matched by Leica at assembly. You should look at the focussing mechanism in the barrel. The helicoid may be twisted, or it may need reshimming.

[chounws]

Hello Jaapv

Thank you for your advised, what your instructed, mean only a focusing mechanism failure to be accurate, not the focal point miss the sensor plane, right?

I do sure that even at infinity, the focus sharp just before infinity.

Choun

 

Sent from my iPhone using Forum Runner

[WestMichigan]

query: are you absolutely sure the optical assembly was fully tightened?

 

I ask because if the optical assembly has been threaded into the focusing assembly a smidge short of all the way (highly technical machinist's measuring unit) that easily will cause the lens to front focus at all distances.

 

Also, is this a fully M mount lens or is it a LTM lens on an adapter?

Because if an LTM to M adapter is to thick it will cause you to experience front focusing as well.

 

I hope you have success getting your Ninety Elmarit up to snuff, I have one of a similar vintage that I am quite fond of. I recently picked up the dedicated lens hood for the 90s &135s of that era and am loving it simply for the tactile niceness of using the dang thing.

 

And yes, I'm a technology/engineering geek. :-D

 

Richard in Michigan

[chounws]

query: are you absolutely sure the optical assembly was fully tightened?

 

I ask because if the optical assembly has been threaded into the focusing assembly a smidge short of all the way (highly technical machinist's measuring unit) that easily will cause the lens to front focus at all distances.

 

Also, is this a fully M mount lens or is it a LTM lens on an adapter?

Because if an LTM to M adapter is to thick it will cause you to experience front focusing as well.

 

I hope you have success getting your Ninety Elmarit up to snuff, I have one of a similar vintage that I am quite fond of. I recently picked up the dedicated lens hood for the 90s &135s of that era and am loving it simply for the tactile niceness of using the dang thing.

 

And yes, I'm a technology/engineering geek. :-D

 

Richard in Michigan

 

Thank you very much Richard,

The lens element tighten in to the barrel well that I'm sure.

And the lens is M mount lens, yes I got it together with the same age Elmar 135, both are beauty and I like the color reproduction of its.

Only the Elmarit 90 not in focus the Elmar is perfect.

I'm looking for the solution if possible, thanks again.

Chounchai, Thailand

 

Sent from my iPhone using Forum Runner

[tobey bilek]

First be sure the last 4 digits of the serial match the engraved numbers inside the mount on the black ring. If they do not match, you have an orphan optics cell mated to a wrong mount.

It can not be made to work. The first clue will be it works at infinity, but not close or the reverse.

 

If they do match, it is a repairman`s job with a collimator to adjust it to do it properly.

 

If you want to play around,order a type 1 90 mm mount from jinfinance on Ebay. Then measure the thickness of the new and old and reduce the thickness of the new to .001" less than the old.. Grind the back side on some 100 grit emery on some glass. Hold down evenly all around with even pressure, slide forward and back,rotate 1/8 turn, repeat, 8 times. Remesure until right thickness is achieved. Then code the pits and you have a lens made the M8.I take no responsibility if you screw this up. I fixed one lens this way because his mounts tend to be .001 thick, sometimes they work, sometimes not.

 

If you can not get it to work, you are only out $15. Then send it to Leica for coding. They will do all the proper adjustments. Do not send an improper pair. They will not get it to work.

[chounws]

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First be sure the last 4 digits of the serial match the engraved numbers inside the mount on the black ring. If they do not match, you have an orphan optics cell mated to a wrong mount.

It can not be made to work. The first clue will be it works at infinity, but not close or the reverse.

 

If they do match, it is a repairman`s job with a collimator to adjust it to do it properly.

 

If you want to play around,order a type 1 90 mm mount from jinfinance on Ebay. Then measure the thickness of the new and old and reduce the thickness of the new to .001" less than the old.. Grind the back side on some 100 grit emery on some glass. Hold down evenly all around with even pressure, slide forward and back,rotate 1/8 turn, repeat, 8 times. Remesure until right thickness is achieved. Then code the pits and you have a lens made the M8.I take no responsibility if you screw this up. I fixed one lens this way because his mounts tend to be .001 thick, sometimes they work, sometimes not.

 

If you can not get it to work, you are only out $15. Then send it to Leica for coding. They will do all the proper adjustments. Do not send an improper pair. They will not get it to work.

 

Thank you Tobey,

I have to digesting your instruction and check the lens, will come back later if more question, thanks.

Choun

[chounws]

First be sure the last 4 digits of the serial match the engraved numbers inside the mount on the black ring. If they do not match, you have an orphan optics cell mated to a wrong mount.

It can not be made to work. The first clue will be it works at infinity, but not close or the reverse.

 

If they do match, it is a repairman`s job with a collimator to adjust it to do it properly.

 

If you want to play around,order a type 1 90 mm mount from jinfinance on Ebay. Then measure the thickness of the new and old and reduce the thickness of the new to .001" less than the old.. Grind the back side on some 100 grit emery on some glass. Hold down evenly all around with even pressure, slide forward and back,rotate 1/8 turn, repeat, 8 times. Remesure until right thickness is achieved. Then code the pits and you have a lens made the M8.I take no responsibility if you screw this up. I fixed one lens this way because his mounts tend to be .001 thick, sometimes they work, sometimes not.

 

If you can not get it to work, you are only out $15. Then send it to Leica for coding. They will do all the proper adjustments. Do not send an improper pair. They will not get it to work.

 

Hi Tobey,

The ordering type 1 90mm mount from Jinfinance on Ebay is the mount as in the picture or the whole barrel of the lens.

Thanks

[chounws]

 

Hi Tobey,

The ordering type 1 90mm mount from Jinfinance on Ebay is the mount as in the picture or the whole barrel of the lens.

Thanks

 

Can someone instruct on how to remove the mount, thanks

 

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[tobey bilek]

That be an odd construction that I thought was limited to my 1969 Summicron 50 mm. It is extra thick, but still has screws. No replacements are available, so I coded with a dremel tool.

 

I loaned my goggled version of 35 2.0 to a friend, then I found we could not get it to code and be read by the camera. Remains a mystery to this day. It has the very same "permanent" mount as your 90.

 

I just looked at my 90 2.8 Elmarit sample and it seems the mount is integral to the whole focus mount. Then I looked at my 135 4.0. Same thing.

 

So it would seem that was standard construction way back when and the screw on flange was something later, probably a cost reduction. I had never given a thought to there being more lenses other than my 50 that were made that way. All the lenses I remounted/coded were 1980 designs and the Jinfinance replacements went well, 5 lenses. All worked ok except for the one I had to grind. There is a tighter/different tolerance from film to digital.

 

Bottom line is someone with proper tools and credentials needs to address this. The adjustment is internal to the focus mount IF THERE IS ONE. And there may not be one because the focus mount is made to the measured actual focal length of the lens cell and not the nominal design length. That is why they are calibrated and made to work together and why both are engraved. It could also be the focus helical has a different pitch thread to match the actual focal length or there could be an adjustment inside. Also possible the actual threads that receive the optical unit can be turned for adjustment. Mine has some black paint in the chrome that perhaps is some type of witness mark.

 

I just looked at my original 50 2.8 and it is a permanent flange also. 35 Summaron is the same.

 

I use the 90 head on a viso and I works well. consider it. You will need the eyepiece from a viso 3, flat bottom, and either a viso 3 box or a 11A which is scarce. A plain 11 can not be adjusted properly. A viso 1 will not hit infinity with a 90.

[chounws]

That be an odd construction that I thought was limited to my 1969 Summicron 50 mm. It is extra thick, but still has screws. No replacements are available, so I coded with a dremel tool.

 

I loaned my goggled version of 35 2.0 to a friend, then I found we could not get it to code and be read by the camera. Remains a mystery to this day. It has the very same "permanent" mount as your 90.

 

I just looked at my 90 2.8 Elmarit sample and it seems the mount is integral to the whole focus mount. Then I looked at my 135 4.0. Same thing.

 

So it would seem that was standard construction way back when and the screw on flange was something later, probably a cost reduction. I had never given a thought to there being more lenses other than my 50 that were made that way. All the lenses I remounted/coded were 1980 designs and the Jinfinance replacements went well, 5 lenses. All worked ok except for the one I had to grind. There is a tighter/different tolerance from film to digital.

 

Bottom line is someone with proper tools and credentials needs to address this. The adjustment is internal to the focus mount IF THERE IS ONE. And there may not be one because the focus mount is made to the measured actual focal length of the lens cell and not the nominal design length. That is why they are calibrated and made to work together and why both are engraved. It could also be the focus helical has a different pitch thread to match the actual focal length or there could be an adjustment inside. Also possible the actual threads that receive the optical unit can be turned for adjustment. Mine has some black paint in the chrome that perhaps is some type of witness mark.

 

I just looked at my original 50 2.8 and it is a permanent flange also. 35 Summaron is the same.

 

I use the 90 head on a viso and I works well. consider it. You will need the eyepiece from a viso 3, flat bottom, and either a viso 3 box or a 11A which is scarce. A plain 11 can not be adjusted properly. A viso 1 will not hit infinity with a 90.

 

Hello Tobey,

Understand, so my one cannot do as your advised to grind down the mount.

I did check the optic element and found the ridge (shown in the picture) that suppose to be the stopping distance of the optic element with the barrel.

I did scratch with fingernail and found the edge of the ridge got a bump (again please the picture, my english may not good enough to explained) do the bump is normal?

How about to grind this bump down very bit?

[peterbengtson]

I loaned my goggled version of 35 2.0 to a friend, then I found we could not get it to code and be read by the camera. Remains a mystery to this day.

 

the goggled 35 brings up the 50 frameline which is magnified by the goggles. so the coding will not work because the frameline sensor is reading a 50 not a 35.

[chounws]

I like to summary this thread with my conclusion that I will try more the lens until sure on what happen before doing any thing. For close distance, I will compensate a bit to the backward point (just a bit) and for infinity I will stop down to f8 then quite sharp. Thank you for everyone.