Focusing an Elmar 2,8/50mm: rangefinder and live view/focus peaking out of sync

[Umfundisi]

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I noiticed that when using my classic Elmar 2,8/50mm there is a significant difference between what the rangefinder defines as in-focus and what live view shows me on the screen/with Visoflex 020. Objects at Infinity are spot on in the rangefinder - but live view tells me a very different story: here I need to turn the focus to the 3m märk to get best results in focus peaking. The results at closer distances are similar. I am baffled because:

- I can replicate this error, first observed on my M10, on my M3 and M6

- ALL my other M lenses (including an LTM Summar and a 90mm Elmar used with an adapter) are spot on in all three cameras.

Any ideas? Any thoughts on how to set about correcting this malfunction - apart from sending in in to LEICA? 

[UliWer]

Are you sure that your lens is completely extended and fixed in this position? 

[Umfundisi]

Abolutely. I made double (no: triple!) sure of that. Also, I conducted the whole testing routine twice ...

[pedaes]

1 hour ago, Umfundisi said:

using my classic

Is it the original or second version? These lenses were not adjusted to 'digital' standards when new, so may need a CLA. Cathy at Will van Manen https://www.kamera-service.info/index.php/en/ did a great job on mine and '6-bit' coded it.

[earleygallery]

2 hours ago, Umfundisi said:

I noiticed that when using my classic Elmar 2,8/50mm there is a significant difference between what the rangefinder defines as in-focus and what live view shows me on the screen/with Visoflex 020. Objects at Infinity are spot on in the rangefinder - but live view tells me a very different story: here I need to turn the focus to the 3m märk to get best results in focus peaking. The results at closer distances are similar. I am baffled because:

- I can replicate this error, first observed on my M10, on my M3 and M6

- ALL my other M lenses (including an LTM Summar and a 90mm Elmar used with an adapter) are spot on in all three cameras.

Any ideas? Any thoughts on how to set about correcting this malfunction - apart from sending in in to LEICA? 

You have live view on an M3 and M6??

Are you saying if the lens is on infinity everything is actually out of focus? If so it sounds like someone has taken the lens apart and not reassembled it correctly.

[TomB_tx]

My 1966 original 2.8 Elmar is spot on from infinity to 1 meter, as is my 1996 2.8 Elmar-M (later design) - down to 0.7 meter. While the Elmar-M has more contrast & resolution, I prefer using the original 2.8 Elmar with the focus lock button. (Perhaps because it was the first Leica lens I used, that sold me on Leica.)

I have a number of M lenses from the 1950-70s and all focus very accurately on M10.

Edited June 1, 2023 by TomB_tx

[lct]

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I would forget focus peaking for this occurrence and redo my test with focus magnification.

[TomB_tx]

For the lens to move out to the 3m mark to match infinity focus it is too far off to be calibration or focus peaking error. Looking at an Elmar it looks like that error is about one helical thread movement. The helical is a multi-lead thread, so perhaps someone separated the helical to clean and lubricate, and started it back one lead off. This would be easy to correct on an older ltm 3.5 Elmar with an external stop-post, but the 2.8 takes more disassembly.

[Umfundisi]

vor 17 Stunden schrieb earleygallery:

You have live view on an M3 and M6??

I guess so. At least I have it on very occasional demand.

I took apart an unused slide frame, removed one of the cover glasses and ground down this cover glass - thus producing a traditional ground glass as used in all Large Format cameras as well as in many analog MF cameras in order to compose a scene and to establish precise focus. I opened and disengaged the back of the M3/M6 and carefully placed my new ground glass on the film guides, fixing it in place with two tiny strips of adhesive tape. Then I mounted the Leica on a tripod, opened the shutter under the B-setting and bingo: using a 10x loupe I could determine with reasonable precision when an object was in or out of focus.

The casual reader might cringe when reading this - but no harm was done to the Leicas involved. And I have the benefit of now knowing what's what as far as the focus-problem is concerned.

Edited June 2, 2023 by Umfundisi
Spelling mistake

[Umfundisi]

vor 2 Stunden schrieb TomB_tx:

The helical is a multi-lead thread, so perhaps someone separated the helical to clean and lubricate, and started it back one lead off

Cool! That's what I wanted to know. I will need to follow someone up on this.

[spydrxx]

1 hour ago, Umfundisi said:

. At least I have it on very occasional demand.

 

I did something similar which has been invaluable. I used a matte focusing screen from a Nikon body, shimmed it properly, and place it on the film rails, open the shutter using the Bulb setting with a locking cable release, and examine the image with a loupe. Doesn't work on most of my Barnacks though, except on a Nicca which has a back which opens like an M3.