How to calibrate focus m10 + 50mm summilux pre ASPH

[Robclarke]

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Hi. I have just got an m10p but on testing it with my pre ASPH summilux I find it back focuses slightly. 

I have used the lens on my film m cameras without being aware of an issue. 

Im just after advice on how to get this corrected as easily and quickly as possible. 

I live in London but bought the camera new from a dealer in the north of England. 

[lexontario]

I have used a tripod, live view and a focus chart to make sure if the lens was back focusing.

[250swb]

Yes be absolutely sure by doing proper test.

You will probably find the lens needs adjusting because the tolerances are much tighter with a digital sensor, but the downside is that Leica would ask you to send in both the camera and the lens at the same time so they can circumvent owner misdiagnosis. This does not mean they calibrate the lens to the camera or visa versa, they set each to it's separate specification datum point. You don't get this problem so much with current lenses as they are already set to the tighter tolerances. That said with some lenses you have to live with some back focusing, somebody who's been using the pre-Asph Summilux on a digital body may be able to help regarding this.

Edited December 7, 2019 by 250swb

[J.Nordvik]

I use this for testing focus: http://www.fotosav.ru/articles/faq/back_focus/back_focus_testing.aspx

 

 

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[J.Nordvik]

I found a couple of other pictures from the same time (2011) showing how to use a matte tape as a focus screen on an M3:

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[Jethro]

Yes, I found my current version 50mm summilux also back focused significantly on my M262. I sent the body and lens back to Leica for recalibration. Leica did the body for free being still within warranty but charged £200 to recalibrate the lens. I’m not sure the lens is much different now, I’ll just have to work within its tolerances though I had really hoped to exploit its f1.4. A part of me is tempted to sell and go back to a summicron and trust in its wider tolerance and better compactness. (My eyesight is fine and regularly tested and I use a x1.4 eyepiece on the camera also to increase the accuracy of the rangefinder patch)

Edited March 25, 2020 by Jethro
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[Good To Be Retired]

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On 12/7/2019 at 4:50 AM, Robclarke said:

 

Im just after advice on how to get this corrected as easily and quickly as possible. 

 

"Easily" would likely mean boxing it up and sending it to Leica.  "Quickly" would likely be whatever is the exact opposite of boxing it up and sending it to Leica.

 

[albertospa]

The pre-aspherical Summilux 50 is characterized, like many other lenses (including also the Summicron in a lesser way), closing the aperture, from a focus shift to short distances. This means that if you have a perfect calibration at f 1.4, the focus will move back to F2 and even further back to f 2.8.
So, in my experience, the ideal would be to have a perfect f-2 calibration. This way you will only have a slight front focus at f1.4 (in practice it never disturbs).
On the M10 you can check all of this in live view.