menos
Mentor
@ mods: I refer to the "… this forum is for the heavy duty tech discussions." bit of the above advice regarding this forum. My post is about adjusting several lenses to a certain rangefinder setting, using shims and following fine adjustment of the matched camera. I think, this falls into this forum, rather then the Leica M forum.
Here follows my original post, I posted on LUF (mixed up places
):
I use mainly 4 Leica M lenses on my M8.2:
50 Lux ASPH,
35 Cron ASPH,
90 Elmarit (latest),
28 Cron ASPH
I was never really satisfied with either the 50 Lux or the 28 ASPH, as normally both should deliver unreasonably sharp focus, when everything is properly adjusted
I therefore conducted a test at infinity, 1m and a sort of close range distance.
All 4 lenses behave differently, as listed in proper order above.
The 50 Lux cannot reach rangefinder alignment at infinity, while the 28 Cron overshoots the rangefinder alignment slightly at infinity.
The 35 Cron and 90 Elmarit lay in between.
In close focus range the 50mm does backfocus by 4 cm.
The 28mm does front focus by 5cm.
Other lenses lay in between.
As I see see the misalignment carefully documented for each lens now, I will have to:
1) Adjust infinity perfectly for the 50 Lux.
2) Adjust close focus correction for the 50 Lux
3) Shim the 35 (if necessary at all, regarding the small difference to the 50mm)
4) Shim the 90 slighly.
5) Shim the 28 the most of the 3 lenses.
For now (until I find the right material for shimming), I adjusted the 90 Elmarit for spot on infinity and compensate for a slight front focussing (about 1 1/2 cm @ 1m).
I use the 50 Lux on the R-D1, which I have matched for it.
All other focus errors for now do fall into the ignorable category, hidden within DOF, sharpening, printing.
Now here is the question (Brian Sweeney - are you reading ? ):
Do I have any failure in my concept regarding needed shimming?
Do you use a specific approach in which setting to start from?
Any failures, you experienced, which I should prevent?
Please no "send the stuff to Leica, let professional service personal conduct the work, …" comments. I am fully aware, of what I am going to do.
This is the first approach of work inside a lens, other than degreasing aperture blades, cleaning lenses, etc. for me.
I post this openly, as I think, other people could benefit from the exchanged information.
Should this exchange of information conflict with forum rules or principles here on the board, I respectfully wish, to be informed and will alter the thread accordingly.
My original post has been made here:
http://www.l-camera-forum.com/leica-forum/customer-forum/121391-lens-adjustment-call-help-brian-you.html
Here follows my original post, I posted on LUF (mixed up places
):I use mainly 4 Leica M lenses on my M8.2:
50 Lux ASPH,
35 Cron ASPH,
90 Elmarit (latest),
28 Cron ASPH
I was never really satisfied with either the 50 Lux or the 28 ASPH, as normally both should deliver unreasonably sharp focus, when everything is properly adjusted
I therefore conducted a test at infinity, 1m and a sort of close range distance.
All 4 lenses behave differently, as listed in proper order above.
The 50 Lux cannot reach rangefinder alignment at infinity, while the 28 Cron overshoots the rangefinder alignment slightly at infinity.
The 35 Cron and 90 Elmarit lay in between.
In close focus range the 50mm does backfocus by 4 cm.
The 28mm does front focus by 5cm.
Other lenses lay in between.
As I see see the misalignment carefully documented for each lens now, I will have to:
1) Adjust infinity perfectly for the 50 Lux.
2) Adjust close focus correction for the 50 Lux
3) Shim the 35 (if necessary at all, regarding the small difference to the 50mm)
4) Shim the 90 slighly.
5) Shim the 28 the most of the 3 lenses.
For now (until I find the right material for shimming), I adjusted the 90 Elmarit for spot on infinity and compensate for a slight front focussing (about 1 1/2 cm @ 1m).
I use the 50 Lux on the R-D1, which I have matched for it.
All other focus errors for now do fall into the ignorable category, hidden within DOF, sharpening, printing.
Now here is the question (Brian Sweeney - are you reading ? ):
Do I have any failure in my concept regarding needed shimming?
Do you use a specific approach in which setting to start from?
Any failures, you experienced, which I should prevent?
Please no "send the stuff to Leica, let professional service personal conduct the work, …" comments. I am fully aware, of what I am going to do.
This is the first approach of work inside a lens, other than degreasing aperture blades, cleaning lenses, etc. for me.
I post this openly, as I think, other people could benefit from the exchanged information.
Should this exchange of information conflict with forum rules or principles here on the board, I respectfully wish, to be informed and will alter the thread accordingly.
My original post has been made here:
http://www.l-camera-forum.com/leica-forum/customer-forum/121391-lens-adjustment-call-help-brian-you.html
ferider
Mentor
I recommend not to touch the 50 due to floating elements.
Adjust the camera for the 50, maybe shim the 90 if you absolutely have to, leave the others as is (a couple of cm don't matter for a {35,28}/2. Overshooting at infinity is OK.
Roland.
Adjust the camera for the 50, maybe shim the 90 if you absolutely have to, leave the others as is (a couple of cm don't matter for a {35,28}/2. Overshooting at infinity is OK.
Roland.
Last edited:
elmer3.5
Well-known
Shimming
Shimming
Hi, i ve performed a few re shimming and focus correction on lenses myself (back and shift).
I did it mainly using the rd1s, but have to say that in the 50 canon 1.2 it was not enough, i had to use the m6.
Even that way i got poor performance on that lens.
I could end this issue with the canon only after the zeiss ikon arrived.
I got perfect focus at 1.2.
My main test on lenses was made at close focus because beyond 3 meters focus problems were not a "problem".
Sometimes shimming was the problem, but in others the distance between rear and front elements was it.
In the case of the summarit 50 1.5 the front element was unscrewed due to use, so i only had to srcew it back into position.
On the jupiter 8, both elements were away by means of a longer thread, i had to sand it away in order to let them get closer (don´t know if i would made such a work on a leica lens)
Perhaps try to use a magnifier and test on a film camera. because at full aperture the epson and the m6 didn´t make the same job (the zeiss neither).
Don´t know if the plane distance may do some difference, perhaps somebody can tell more about this.
Hope this helps you out!
Bye!
Shimming
Hi, i ve performed a few re shimming and focus correction on lenses myself (back and shift).
I did it mainly using the rd1s, but have to say that in the 50 canon 1.2 it was not enough, i had to use the m6.
Even that way i got poor performance on that lens.
I could end this issue with the canon only after the zeiss ikon arrived.
I got perfect focus at 1.2.
My main test on lenses was made at close focus because beyond 3 meters focus problems were not a "problem".
Sometimes shimming was the problem, but in others the distance between rear and front elements was it.
In the case of the summarit 50 1.5 the front element was unscrewed due to use, so i only had to srcew it back into position.
On the jupiter 8, both elements were away by means of a longer thread, i had to sand it away in order to let them get closer (don´t know if i would made such a work on a leica lens)
Perhaps try to use a magnifier and test on a film camera. because at full aperture the epson and the m6 didn´t make the same job (the zeiss neither).
Don´t know if the plane distance may do some difference, perhaps somebody can tell more about this.
Hope this helps you out!
Bye!
menos
Mentor
I will not dig deep into the 50 Lux (didn't went past unscrewing mount and focus ring).
I do plan to adjust the camera to the Lux and shim the other 3 lenses between lens and lens mount, to take them further away from the film plane according to how much they differ to the Lux.
The off focus especially with the 28 Cron is very obvious, which is, why I adjusted the camera, to fit the 90mm perfect and sit closer to the 28mm as a compromise.
I have yet to find the right material, to do the work.
menos
Mentor
Thanks Elmer for sharing your experience ;-)
One question regarding the 50 Lux ASPH:
The lens mount of my used sample is brassed in the area, where the focus unit contacts the mount. Is this supposed to be from stock, or is it due to wear?
As the focus unit does show a slight play in this area and the fact, that technically less friction (and therefore a smoother operation of focus) is achieved with the use of two different materials (one brass, one chrome plated alloy or other different material from brass), I doubt, that both the slight play and the slight sticky focus might be caused partly by a worn lens mount?
Can somebody, who unscrewed a 50 Lux ASPH lens mount before confirm this?
One question regarding the 50 Lux ASPH:
The lens mount of my used sample is brassed in the area, where the focus unit contacts the mount. Is this supposed to be from stock, or is it due to wear?
As the focus unit does show a slight play in this area and the fact, that technically less friction (and therefore a smoother operation of focus) is achieved with the use of two different materials (one brass, one chrome plated alloy or other different material from brass), I doubt, that both the slight play and the slight sticky focus might be caused partly by a worn lens mount?
Can somebody, who unscrewed a 50 Lux ASPH lens mount before confirm this?
Phil_F_NM
Camera hacker
Regarding material used for fine shimming, I have used copper plating for finishing outdoor decorative elements on old houses. This material is a copper sheet with adhesive on one side. It peels off like a sticker and can be layered up to an appropriate thickness. I've used this on a 90mm Elmarit, 50mm Jupiter-8 among others with good results. it should be able to be found in a home repair store. If not, ask and some could get sent. We have a roll of it; probably 20m x 120mm. Just .3m of this material is enough to shim many lenses. A warning though, it is on the order of a fraction of a millimeter thick, so I'd use it only for fine adjustment at the end.
Good luck!
Phil Forrest
Good luck!
Phil Forrest
menos
Mentor
Thanks for the tip on the material Phil - I will investigate into the local home build markets also.