| Author |
Message |
    
Tach
Tinkerer
Username: Tach
Post Number: 1
Registered: 08-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 09, 2011 - 10:58 am: | 
|
Hi, I recently bought a mint Yashica FX-2 with a 50mm f/1.7 ML lens. According to the seller, the camera was bought in the 70's, used once in a trip, and went into a cupboard until four years ago, when it had a CLA and seals replaced. Then, back into the cupboard.
I forgot to check focus at infinity, and when I got home I realised that I can't get a sharp image on the viewfinder at infinity.
Also, when I focus to an object at a known distance, say 3m, measured by tape, the focus ring on the lens says that it's at 10m.
In order to check focus on the film plane, I taped a clear negative with some lines scribbled on it on the film rails in the back, and checked focus with a known good camera+lens (my F3 and nikkor 105), according to https://kyp.hauslendale.com/classics/collimator.html.
Problem is, focus is perfect at infinity on the film plane :/. So, it seems that it is a problem on the focusing screen seating.
So,
i) Do you see any problems with my analysis? Am I overlooking something?
ii) What should be my first steps to solve this? Is it doable for a beginning tinkerer with time on his hands? |
Dirbel
Tinkerer
Username: Dirbel
Post Number: 50
Registered: 04-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 09, 2011 - 11:51 am: |
|
Hi back,
Another failure source would be the mirror. If the angle of the mirror is not 45 degrees, you will get uneven focus along the vertical axis of the finder image.
I don't have a FX-2, but the FX-1 should be similar:
Removing and reseating the focussing screen might be possible through the lens mount, check for small screws in the upper left and right corner of the lens mount.
Re-adjusting the mirror position would be more work, I can't see an adjustment inside the mirror box.
HTH,
Dirk |
Donnie_strickland
Tinkerer
Username: Donnie_strickland
Post Number: 128
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 09, 2011 - 11:55 am: |
|
"i) Do you see any problems with my analysis? Am I overlooking something?"
Your mirror could be out of alignment. The focus would be correct at the film plane, but incorrect when looking through the viewfinder. I'm not sure if the FX-2 has an adjustment for the mirror height. |
Michael_linn
Tinkerer
Username: Michael_linn
Post Number: 23
Registered: 04-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 09, 2011 - 03:22 pm: |
|
On this model, and several other Yashica-Contax models, the mirror angle is set by a stop in the mirror box on the rewind side. There is a plastic bushing on the end of it. If it goes missing the mirror will sit too low. I'd check that first as that is the easiest to inspect. The adjustment for the stop is on the inside of the mirror box which requires some disassembly to access.
If it had a "CLA" it's possible that the tech removed the focusing screen holder as the mirror bumper is attached to that, which is held in place by three screws accessible at the front of the mirror box. So it's possible that the focusing screen is upside down or otherwise skewed. |
|
