M6 focus adjustment

[valdas]

I have noticed quite pronounced back focus when shooting with my M6 (maybe som 3 cm at 1.5-2 meters). The issue is the same with all lenses. RF aligns at infinity (as far as my eyesight can tell). So probably some camera focus adjustment needs to be made. So the question - is it a DIY job or I'd better send it to professionals?

 

[Fraser]

I have noticed quite pronounced back focus when shooting with my M6 (maybe som 3 cm at 1.5-2 meters). The issue is the same with all lenses. RF aligns at infinity (as far as my eyesight can tell). So probably some camera focus adjustment needs to be made. So the question - is it a DIY job or I'd better send it to professionals?

i adjust my M9 myself but thats easier to check, never really needed to adjust my film leicas, but what I would say is don't send it away have you not got a local camera repair shop that could do it?
As its not a difficult job with the right equipment.

 

[valdas]

i adjust my M9 myself but thats easier to check, never really needed to adjust my film leicas, but what I would say is don't send it away have you not got a local camera repair shop that could do it?
As its not a difficult job with the right equipment.

In the place I live local repair shop does not have much experience with Leica, but still it is an option. I was thinking that if it's not too complicated I can do it myself. Some years ago I successfully did an infinity adjustment based on some instructions I found online, but maybe my case is more complicated now...

 

[mod2001]

I have noticed quite pronounced back focus when shooting with my M6 (maybe som 3 cm at 1.5-2 meters).

One question, how do you notice a 3cm back focus at this distance? Even with f1.4 and a 50mm lens you have a depth of field of over 7cm @1,5m and over 13cm @2m? Did you test it with a ruler or something similar and the camera on a tripod? I would assume that you can't see it in a normal foto on film which is a little bit more forgiven in this case than a digital sensor.

Its the first time that I hear words like back- or front focus in context with 35mm film cameras, thats why I ask?

Yogi

 

[valdas]

One question, how do you notice a 3cm back focus at this distance? Even with f1.4 and a 50mm lens you have a depth of field of over 7cm @1,5m and over 13cm @2m? Did you test it with a ruler or something similar and the camera on a tripod? I would assume that you can't see it in a normal foto on film which is much more forgiven in this case than a digital sensor.

Yogi

Yes, when I suspected this (some shots appeared to be out of focus) I tested on the tripod with a ruler and this was confirmed.

 

[mod2001]

Yes, when I suspected this (some shots appeared to be out of focus)

wow, I doubt I would realize this small back focus in the real world. Anyhow, you should fix it, just alone to get rid of this 'bad feeling' that the focus is maybe not correct. One of the reasons I never bought the Zeiss Sonnar C 50mm, alone the thought something is wrong either at f1.5 or at f2.8 would drive me crazy, even if it is obviously not a big problem in most of the cases.

Yogi

 

[Mjd-djm]

Be aware that the lens could be the problem especially if it appears to focus to infinity but focus is still off. The rangefinder images coninciding at infinity when the lens is focussed to infinity should usually mean accurate focus throughout the focus range.

If you adjust it then you might affect the focus with other lenses. Having said that I have done this adjustment with a VC 50mm 1.5 Nokton on an m6 before. Even though it focussed to infinity the focus was off, so I adjusted it and it worked. It's is simple to do but a little fiddly depending on how tight the screw is. I only used that lens at the time so it wasn't an issue for me. I used it with various other lenses before I got the Nokton with no problems. Unfortunately tolerances between camera and lens don't always combine to provide accurate focus.

 

[valdas]

wow, I doubt I would realize this small back focus in the real world. Anyhow, you should fix it, just alone to get rid of this 'bad feeling' that the focus is maybe not correct. One of the reasons I never bought the Zeiss Sonnar C 50mm, alone the thought something is wrong either at f1.5 or at f2.8 would drive me crazy, even if it is obviously not a big problem in most of the cases.

Yogi

well, I said 3 cm from my memory, it could be a bit more, but if you focus from 1.5 meter on eyes with aperture wide open 3 cm off is noticeable.

 

[mod2001]

but if you focus from 1.5 meter on eyes with aperture wide open 3 cm off is noticeable.

Well, can't argue with that. Is probably one of the cases where I would see it too.

Yogi

 

[Sarcophilus Harrisii]

You really need to check the lens focus, and them ensure the rangefinder agrees with that. If, hypothetically, the lens is not sharp at infinity when at the infinity stop, it won't matter if the RF focus looks good at infinity, if it does not match the lens. By checking the lens focus first, and ensuring this is correct, all you need then do is get the RF correct and, having done this, you know the two must match. You should always inspect the relationship between the RF and lens at close range, too, it's a good cross check to ensure your infinity settings are really good. If they're truly accurate, the focus should also match exactly near the minimum focus distance as well. With a RF featuring interchangeable lenses, it would be prudent to check the focus of several because, naturally, assuming the camera lens register is optimum, when the RF is correctly set, focus should be very accurate regardless of which lens is fitted.
Cheers,
Brett

 

[valdas]

You really need to check the lens focus, and them ensure the rangefinder agrees with that. If, hypothetically, the lens is not sharp at infinity when at the infinity stop, it won't matter if the RF focus looks good at infinity, if it does not match the lens. By checking the lens focus first, and ensuring this is correct, all you need then do is get the RF correct and, having done this, you know the two must match. You should always inspect the relationship between the RF and lens at close range, too, it's a good cross check to ensure your infinity settings are really good. If they're truly accurate, the focus should also match exactly near the minimum focus distance as well. With a RF featuring interchangeable lenses, it would be prudent to check the focus of several because, naturally, assuming the camera lens register is optimum, when the RF is correctly set, focus should be very accurate regardless of which lens is fitted.
Cheers,
Brett

yes, that's what I am planning to do - just need some tools and time...

 

[Mark C]

I do some adjustment on my own, but cannot match the accuracy of someone like Sherry or DAG that has the proper tools. As already said here, really check infinity precisely, that sometimes drifts off a bit for some reason. I use a distant antennae as a target for the rangefinder, and have a lens that I know is spot on from checking with a freshly adjusted camera. I see slight variations on this from lens to lens.

If the rangefinder is exact at infinity, and the error only exists close, then it is likely to be the adjustment cam I would call "rate", which matches the rangefinder movement over the full range. That is the adjustment that I find very challenging to get exact. I've gotten my M4-2 very close, but it took a lot of fussing, but still barely adequatee for the most demanding lenses.

I don't know where you are located, but I haven't run into a local repair shop that could get even remotely adequate adjustment. Most don't even understand the level of precision that rangefinder is capable of. I'm sure there are exceptions, but I'd certainly look for someone with extensive Leica experience.

 

[mpaniagua]

Send it to a professional. Period.

I sometimes fiddle with my FSU but never with my Leicas. Will strongly recommed not to fiddle with them unless you are confident on your skills. FSU and Leicas my look similar but they are pretty much differents beast under the hood. Do yourself a favor and send it to an experienced tech (DAG,Sherry,etc.)

On the same note, dont fiddle with your Leica lens. Its ok to fiddle with FSU lens, have done it myself, but Leica (or Zeiss or CV for that matter) are expensive and there is a high risk to get something wrong or damage (or loss) something. If you are the DIY kind practice with cheaper cameras (FSU or so) until you are confident with your skills and tool sets.

Regards.