Canonet RF alignment - help needed

[BlueWind]

Hello. Can someone please tell me how/where can I adjust the horizontal RF alignment in my Canonet (it is a plain Canonet, no numbers or letters added).
Photos of the camera with the top removed
http://public.fotki.com/BlueWind/canonet-rangefinder/
Thank you
Joao

 

[John Koehrer]

Horizontal suggests that the camera doesn't focus correctly, either at infinity or a closer distance. Watch the small mirror(2) as you adjust the focus. It should rotate. I suspect it's either D or E. one will be a close focus stop and the other will be infinity. C is the mounting screw for 2 & you shouldn't need to touch it. It should be sealed with paint.
Adjustment is going to be a barely perceptible movement of the screwdriver. Some pressure applied on the screw may do it. A 1/16 turn is too much

 

[BlueWind]

Hello
Thanks for your input. The small mirror "2" does not move at all when focusing. The small "c" screw behind the mirror controls the vertical alignement, that was easy to find. I tried to unscrew (almost totaly) the screws "D" and "E", they are fixing the round metal base that holds the mirror “2”. You may be right, and I will give another try at this possibility. OTOH I’ve read somewhere that that mirror is supposed to be fixed and some movement related to the parallax correcting device is indeed responsible for the coincidence of the images in the viewfinder (!!!). It is not easy to me to understand that, and I couldn’t find more details… Interestingly, there is an obvious change in the separation of the images in the viewfinder when I change focus, and the small mirror does not seem to move at al.
Any way, one positive point: using scale focusing, the lens gives pretty sharp images. Examples here:
At close distance
http://www.flickr.com/photos/joaofreitas/2979551064/
At infinity
http://www.flickr.com/photos/joaofreitas/2979551068/
Best regards
Joao

 

[John Koehrer]

Joao,
Didn't realize that piece was stationary. Looking at the pictures it appears that #1 is the moving part. That points at either "A" or "B" being the adjustment. What you're looking for is a physical stop for the moving section, if either "A" or "B" are eccentric that will move the end point of the lens. I suspect it's "B" since it's at the end away from the pivot point.

 

[BlueWind]

Hello John
Things do not seem so easy, I unscrewed screw "A " (no change) and "B" (also no change in the view finder). Interestingly the all the moving parts I see seem aimed at controlling only the movement of the frame for the paralax correction !!!. I will explore the possibility of some moveable part - that seems now to be fixed - having a VERY SMALL range of movement. When focusing there are also moving parts under the floor of the section at the left side, under the first diagonal mirror.
Due to lack of time - and ageing eyes - this is a work I will be doing slowly. I will hopefully post some results in the near future.
Thanks for your interest and sugestions
Joao

 

[Nicholas Lindan]

Does the spot in the viewfinder move when you focus? If so then something in the rangefinder has to move when focusing and that thing is what needs the alignment.

Mirror 1 looks like it rotates to move the frame lines when focusing. It may also act as a prism where it lets through the beam for the rangefinder window. If you look through the viewfinder while moving 1 with a q-tip or some-such does the focus spot move?

Normally in a rangefinder the small mirror 2 rotates and is on a shaft that connects to a lever arm that rides on the back of the focusing helical. If the pivot for the mirror is gunked up with dried grease then this may be the problem. The horizontal alignment screw in a rangefinder camera is usually accessible without having to remove the top cover of the camera: are there any access points in the top cover - holes that are covered with a screw, often a funny-headed screw? It is also possible the horizontal alignment is accessed inside the camera with the back open. On a Leica the adjustment is on the roller at the end of the lever arm, referenced above.

 

[BlueWind]

Nicholas
The spot in the viewfinder moves when I focus, however it stays always at a certain distance from the patch.
Mirror 1 seems to be in charge of the framelines only, I tested its movement while looking through the viewfinder, only the framelines move.
I agree with you that the small mirror 2 should be the crucial point to move the spot, for several reasons: 1) it’s logic 2) the “c” small screw behind mirror 2 controls vertical alignement, this one is very easy to correct
3) When I unscrew the two small screws that hold the mirror 2 to its base, the mirror moves freely - and so does the spot.
Next goal : to find a way to move the cylindric base of mirror 2, it must turn around its axis, it is what makes sense to me. It looks too big just for holding such a small mirror
I will post some updates as soon as I have new findings.
Thank you for your input
Joao

 

[John Koehrer]

The movement is usually caused by a lever or cam rotating the mirror. On the Leicas this is behind the lens & is accessed by removing the lens. On a camera like this you may have to remove the lens mounting plate to gain access.

 

[BlueWind]

I found it!

Hi
The screw that controls the horizontal RF movement in placed just in front of the viewfider lens, almost under the first diagonal glass, in the left side of the pictures. We need to remove the top of the camera, then the RF chamber is covered with a metal plate with a hole - the screw can be reached through this hole, screwdriver vertical!!! This screw moves an excentric piece under the floor of the RF chamber, and it makes the images coincide or not. That excentric metal piece is controled by another part (also under the RF floor) coming from the lens.
It was not necessary to remove the covering of the RF chamber - things would probably have been more evident ... I was insisting in looking at the wrong place, and I am very grateful for your sugestions and interest.
Thank you again
Joao