Rangefinder Adjustment Help

[Ken.Cartouche]

Hi, everyone!

When I took my Canon P out to shoot this weekend, I realized that my rangefinder has apparently gotten out of alignment. When I tried to adjust it back yesterday, I found that I could never get the patch to line up at infinity. I tried with two different lenses (that, admittedly, have never been tested on any camera but this one, though one of them DID line up at infinity when I first got it.) So, then I decided to try focusing at 1 metre, measured with a steel tape measure from the target to the film plane indicator on the top of the camera. I couldn't get it to focus at that distance, either.

To adjust, I removed the bezel from around the round window on the front and used a micro screwdriver to rotate the prism in its socket. The image in the viewfinder moves from side to side, but never lines up. I turned and turned and turned, until I was afraid the prism was going to completely unscrew from the camera, but all the image did was shift slightly from left to right, never aligning. The other alignment, the up-down alignment, worked fine.

So, am I doing something wrong? If I take off the lens and push the rangefinder arm all the way inward, should I get rangefinder alignment of an object at infinity (or at least a quarter mile away or so)? If I should, I don't. The camera hasn't been subjected to any bangs or bumps, though it has probably gotten vibrated and jostled some from being carried in my messenger bag for a couple of days prior to me noticing the alignment being off. Still, I wouldn't expect any of that to cause the rangefinder to become unadjustable, which is what makes me think that I'm missing something important.

 

[back alley]

rf adjustment on the p is done on the front of the camera body.
there is a screw that needs to be removed, next to the prism window, and then use your screwdriver to make tiny adjustments.

 

[AndersG]

Whatever you do: Think twice before changing the near adjustment on the range finder follower roller. If it is like on the Canon 7 you can turn it one way with a small screwdriver but the other way only with an appropriate spanner-like tool that you will probably have to manufacture yourself.

OTOH this setting is probably less likely to go out of adjustment by itself.

/Anders - who has tried this once - and didn't have the tools needed to make the custom tool..

 

[Ken.Cartouche]

rf adjustment on the p is done on the front of the camera body.
there is a screw that needs to be removed, next to the prism window, and then use your screwdriver to make tiny adjustments.

I got that. That little screw is just a cap to cover the hole where the adjustment screw is, but that adjustment screw controls the alignment of the horizontal lines in the rangefinder patch. What I need to adjust is the alignment of the vertical lines, which, as I understand it, is done by rotating the round prism under the removable bezel on the front of the camera. Rotating this prism does make small adjustments to the alignment of the vertical, but never actually brings them together as I understand it should.

 

[Ken.Cartouche]

Whatever you do: Think twice before changing the near adjustment on the range finder follower roller.

I wouldn't even know how to start the process for doing that. I'm only interested in adjusting the rangefinder patch alignment using the screw adjustments on the front of the camera.

Unless the problem I'm having goes beyond that, of course.

 

[marek_]

Yes, rotating the prism under the bezel should adjust vertical alignment. But it's been noted that adjusting vertical alignment can then affect horizontal alignment. So you may have to adjust and check both. I did this with my VL recently. Good luck.

 

[Ken.Cartouche]

Yes, rotating the prism under the bezel should adjust vertical alignment. But it's been noted that adjusting vertical alignment can then affect horizontal alignment. So you may have to adjust and check both. I did this with my VL recently. Good luck.

Thanks, marek. Yes, I've adjusted both. Verticals simply will not align at infinity. And I mean, they're WAY off. Oddly, with a lens focused at infinity (or the rangefinder arm pushed all the way in), the farther away an object is, the more out of alignment it appears, which is just the opposite of what I would have expected.

 

[AndersG]

I wouldn't even know how to start the process for doing that. I'm only interested in adjusting the rangefinder patch alignment using the screw adjustments on the front of the camera.

Unless the problem I'm having goes beyond that, of course.

Changing this adjustment is only needed when you cannot get the correct horizontal alignment at both close distance and infinity using the other adjustments. I have a scan of the/a Canon 7 repair manual that describe the iterative process. Your vertical alignment problem sounds worrying and needs to be figured out first.

In the end I got my Canon 7 adjusted by a repairshop when it also needed to get its shutter overhauled.

[EDIT]I should add that, at least the common, FSU LTM cameras also have these two adjustments for horizontal alignment so it is likely that Canon had it before the 7 too. The russian variant needs no special tools but is more easily disturbed.[/EDIT]

/Anders

 

[Ken.Cartouche]

...Your vertical alignment problem sounds worrying and needs to be figured out...

...I got my Canon 7 adjusted by a repairshop when it also needed to get its shutter overhauled.

The shutter on this P does seem to need some work. 1/15 second is more like 1 second, so the speeds are definitely off to a greater or lesser degree. I may just use scale focusing for now until I can send it off for repairs.

I've heard Mark Hama is the go-to man for these Canon rangefinders; any other repair recommendations?

 

[Mackinaw]

…...I've heard Mark Hama is the go-to man for these Canon rangefinders; any other repair recommendations?

Youxin Ye works on the P. DAG probably would too as well as Ken Ruth. All are top-rated.

Jim B.

 

[marek_]

When I adjusted my Canon VL, it was after I'd taken the top plate off to clean out some dust. I took the prism off that adjusts vertical alignment, and in the process moved it out of it's correct position. To unscrew the prism you have to align the notches that let you rotate the prism for vertical alignment with another two underneath that are used to unscrew the whole prism from the rest of the rangefinder mechanism. Readjusting it afterwards only required a slight turn. I turned it a quarter to see the extent of the miss-alignment - it went out quite a bit.

Try lining up these notches and then see if the whole prism unit screws in any further. If it does then this looseness may be what is cause the large miss-alignment.

If that doesn't work I'm guessing there must be something else which is causing the issue.

Good luck.

 

[Ken.Cartouche]

Marek,

When I read your post, I thought you had hit the nail squarely on the head. I had turned and turned and turned the prism in an attempt to align the verticals, and I thought that I had probably turned it too far. So, I went ahead and removed the rotating glass completely and looked for the notches underneath.

Well, on the P, there don't appear to be any notches like on your VL. So, I'm still stuck. I went ahead and screwed the glass back in completely, like it was when I initially found it, and it's no better than before.

The weather has cleared sufficiently for me to finally see the moon, and when I set my lens to infinity I see two little crescents next to one another. They are close, but don't touch at all. Dang.

And just so I know it's not my lenses, I obtained from a friend a LTM camera with a lens that I know are in good alignment. I tested her lens on my camera, and my lenses on her camera. My lenses work great on her body, and her lens is no better than mine on my P. Double-dang.

 

[marek_]

Hi Ken,

I'm sorry to hear you haven't got much further. Here's an exploded diagram of the Canon P top plate, knobs and switches. C2191 and C9025 have two matching notches (2&8 o'clock).

Hope this helps.