Rangefinder double vision indicates, incorrectly, that image is not in focus

[jrp]

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Most of my lenses work as well as can be expected on an M9, but I have a 75mm f2 that I thought back focused (when taking closer shots). I have now confirmed this to myself by finding that distant subjects never merge into a single image in the rangefinder; I get a double image. The resulting pictures are, actually, in focus, however.

 

Is there anything that I can do myself to calibrate, or is it a matter of sending it in? (My 75mm has some focusing ring resistence at around 0.75mm, as others here have reported.)

 

(The only other lens that troubles me is the 28mm f2 which may just have a softer rendering, or it may also be back focusing, I'm not quite sure.)

[ho_co]

Adjusting lens focus requires special tools. Not something to be tackled at home. I'd have Leica look at it.

[thighslapper]

75/2 and 50/1.4 have floating elements and are difficult to adjust for all distances.

 

Rangefinder calibration issues are very much more noticeable with these lenses and it may be that slight miscalibration that isn't obvious with other lenses shows up with the 75/2. Check very carefully with another longish focal lens lens if you have one.

 

I've had several 50/1.4's that have been well out at infinity so you may well be right. Factory fix only I'm afraid.

[jrp]

My 50mm f1.4 and 90 f2 seem close to perfect, so it's a matter of relegating the 75 to the NEX, or going back to the factory, as you say, I guess.

[jaapv]

It happens and usually it has no impact on focussing accuracy. If that is the case I would advise you to ignore it. If it offends against a sense of perfection, Leica can correct it for you.

[jrp]

Unfortunately it has an impact on focusing closer up.

[Dan Bachmann]

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Something quick and easy to check and fix are the screws that hold the M mount on. Some are held on by screws that allow 6 bit mounts to be added/replaced. I had a lens with the issue after it was convered to a 6 bit mount (not by Leica). I tightened the screws and the problem was solved.