Lens Focus Difference Between Different M Bodies?

[NicCouryPhoto]

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hey all,

Can there be a focus issue of the same lens between different cameras?

I have a perfectly good pre-ASPH vers. 3 50 Lux and it's sharp and focuses well on my M240, but a friend tried it on his M10 and said it back-focused.

Seems like a camera calibration issue more than a lens issue.

I've shot the lens with zero focusing issues and it was sharp and in focus. The M10 camera apparently backfocused, which a CLA would fix.

[jmahto]

RF calibration difference may be the cause. You can also try to focus at infinity distance that doesn't require RF. Just turn the focus tab to infinity lock and check the picture of far away object. If it is sharp in both the cameras then most probably lens is fine and RF calibration is needed for closer distances (where RF focusing is used).

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[NicCouryPhoto]

RF calibration difference may be the cause. You can also try to focus at infinity distance that doesn't require RF. Just turn the focus tab to infinity lock and check the picture of far away object. If it is sharp in both the cameras then most probably lens is fine and RF calibration is needed for closer distances (where RF focusing is used).

 

Ok thanks. That's what I'm thinking the issue is.

[Gregm61]

Oh yeah.....between the three I have (M262, MP240 and M246) there are certain lenses than don't work as well with one body but are spot on with another, primarily longer lenses. I have a 135mm f3.4 APO Telyt, purchased brand new that focuses perfectly on the M246 and pretty well on the MP240 but isn't matched well at all with the M262.

 

Same situation but different bodies with 75 and 90mm f2 APO Summicrons.

 

Of my three bodies the M246 seems to have the best rangefinder calibration across all my lenses and I need to send my M262 in to have it cleaned and adjusted and the M262 is the one body of the three I purchased brand new.

 

It's enough when you get your lenses to work well on your own bodies, much less worry about how well they're calibrated on someone else's camera. They just need to get their own lenses, LOL.

Edited September 19, 2018 by Gregm61

[adan]

This is why the late great Rock'n Roll and Leica photographer Jim Marshall once said, "Once I find a lens that works well with a body, I never take it off again."

 

Of course that meant he often carried 4-5 Leicas - in this shot, with 21, 35, 50, and 90 (at waist, behind hand) lenses: http://blog.defgrip.net/2010/03/jim-marshall/

[jaapv]

This is why one should send the whole system in for calibration to a trusted repairer if such issues appear. All lenses and cameras must be calibrated separately to a common standard.

[DaveM3]

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I'd be interested if someone could explain how a lens is actually calibrated - I mean what physical aspect of the lens is adjusted?  Logic says that it must be the relationship of the focus ring adjustment position relative to the cam position, so is it simply a case of rotating the cam to precisely the correct relative position and then locking it down? 

[TomB_tx]

Calibration varies depending on lens model. Some have adjustment as you indicated, others require internal shimming. More modern lenses tend to have easier adjustments than early lenses, where the final grinding of the cam surface was matched to the optical cell to be used.

[Gregm61]

I'd be interested if someone could explain how a lens is actually calibrated - I mean what physical aspect of the lens is adjusted?  Logic says that it must be the relationship of the focus ring adjustment position relative to the cam position, so is it simply a case of rotating the cam to precisely the correct relative position and then locking it down? 

 

Read the link below as Ming offers to do this for local clients...it is possible to get an entire set of lenses calibrated to one body, but does require some lens disassembly and the rate at which many change/exchange/upgrade bodies seems like a waste of time and money. I utilize a set of lenses between three M digital and two M film bodies. Which one would I choose to be calibrated? Lordy lord. I just choose to send bodies in for periodical cleaning and adjustment to factory standard, assume the lenses I buy new are within spec unless I see something grossly off and just live with the fact this system is, what it is, which isn't perfect.

 

https://blog.mingthein.com/2012/06/08/leica-m-rangefinder-calibration-service/

Edited September 25, 2018 by Gregm61