Adjusting R/F of M2

[payasam]

The range-finder of my M2 is off. Much of my work is done at near distances and wide apertures, and that is where the problem shows up. Infinity (the moon) was not aligning correctly. I have managed to set that right, and there is a definite but insufficient improvement in near-distance focussing. I can manage by compensating -- that is, by deliberately mis-focussing -- but I shall be obliged if other members can tell me how to handle the 1 metre adjustment.

 

[VictorM.]

Here's M3 instructions: http://www.mediajoy.com/en/lrc/rM3/r_adjust1.html . How often do you need perfect infinity focus at wide apertures? You may want to adjust the near distances more accurately.

 

[payasam]

Thank you, VictorM. You're quite right that near distances are more important than infinity from a practical stand-point. Getting infinity right is important, though: it has often been described as the place to start, a sort of reference point.

The instructions to which you point me are too perfunctory to be of any use. In particular, it seems from them that there is a single adjustment for horizontal alignment. Rather better instructions are to be had as a PDF file from the pentax-manual web site. Trouble with those is that the descriptions in the text do not match the names used in the labels of the photos.

 

[maddoc]

Actually there are two adjustments for horizontal adjustment (infinity set and gain) and one for vertical adjustment (behind the small cover-screw). The one screw on the roller-arm which is next to the lens sets the infinity or starting point for the rangefinder. When I received my M2 focus was well off at all distances and I adjusted this screw to set focus at infinity correct and then the other distances became OK, too. Adjusting infinity is usually the only adjustment to make. The other horizontal adjustment sets the gain of the rangefinder, that is the traveling increment of the arm for a certain movement of the lens-cam.

 

[payasam]

Thank you, Gabor. Infinity is now all right on my camera, but not near distances (1m to 2m). Maybe I should post a close-up shot of the three adjustment points, labelled A, B and C so that someone can guide me through. I shall touch nothing until I know exactly what I am doing. Don't want to mess up anything. As I said in my first post, I have the option of compensating for the R/F error.

 

[Melvin]

Payasam, PM me your e-mail and I will send along detailed instructions that another member was kind enough to send me.

 

[payasam]

Thank you, Melvin.

 

[payasam]

Only a test with film will show if I've managed to get it right, but I think I have. I read, several times, what Melvin kindly sent (which I happened to have already) as well as the instructions on a site charmingly named jumboprawn. Then spent a while moving the mechanism with a finger tip to understand how it works. Luckily my collection of screwdrivers had two that were just right, and I took care to ensure that, while I might mess up the adjustment, I wouldn't cause damage. It was a tedious business -- seemingly endless tweak and check, tweak and check -- and I hope I don't have to do it again.