Lens adjustment question

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Again - another film test with my 50 F2 summicron (258xxxx) shows that the RF (M6) is focusing slightly behind the lens. The lens scale is spot on when I measure out distances of 1,2,5 10 and infinity as well as doing the self reflection test. As the scale is correct throughout the range I assume the arm length is right but the roller needs reset but if I do this infinity will not line up (it will be short)! I obviously need to change the lens focusing barrel to lens cam/element relationship. Also the dot for the aperture indication is not in line with the infinity mark - I reckon after years of use or some heavy handed focusing it has sliped/ been forced off alignment. Can someone describe how this is done - I have removed the mount and can see 2 side by side screw heads that can be accessed when you rotate the focusing ring - do these lock the lens cam/element barrel to the focusing barrel? Before you reply - 'stop messing about and get it to a Leica tech'- if it was mint I probably would but it's not rocket science and if a straightforward DIY adjustment will bring it back to spec I will give it a go.

-- John Griffin (john@griffinphoto.u-net.com), March 27, 2002

Answers

John,

What do you mean that the RF is focusing behind the lens? Do you mean the prints show a sharp nose and soft eyes?

It seems like a simple trial and error operation. Loosen the screws and turn the helical one way, tighten and take a tripod mounted photo of newsprint from an angle; loosen and turn somemore in the same direction; take picture; repeat; then repeat turning the opposite way.

Think of it like bracketing. Find the best point and set it.

Record keeping is the most important.

-- chris chen (chrischen@msn.com), March 27, 2002.


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