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Markus
Tinkerer
Username: Markus
Post Number: 9
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 16, 2007 - 05:07 pm: | 
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I was trying to adjust the focus mechanism on a pretty beat up Rolleicord Va. On the focus knob side, the wegde that tightens the slider that the lens board is attached to was loose, so I tightened it and everything seemed fine. Then after more closely inspecting the lens board, I noticed that the at the infinity setting, it is not entirely flush with the camera, there is a very slight gap in one of the two bottom corners (probably not enough to matter much in practice). Is there a way, other than bending, to fix this? I tried to adjust the sliders that the lens board is attached to on both sides simultaneously, but that did not quite do it.
I guess, a more general question would be, if there is a way to check whether the lens board is parallel to the film plane (and I mean something that I can do at home)?
- Markus |
Ethostech
Tinkerer
Username: Ethostech
Post Number: 79
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 18, 2007 - 05:10 am: |
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What you refer to as a "lens board" is actually a fairing of aesthetic value. You are referring to front panel which is covered with leatherette. Yes ?
The actual lens/shutter assemby is carried (ie: mounted) on a robust steel sub-frame. The "len's board" fairing is then shimmed to aesthetic true and held by four screws. Someone may have serviced the shutter and not properly shimmed the lens board to complete the job. In such instance the lens performance is not impaired in any way.
But even if the subframe is marginally out of parallel with the film-plane, the error at the edge of the lens will be much much less than that which you might be able to measure at the edge of the plate and the worse case scenario would be some edge softening of the negative definition at full aperture.
I would suggest you load the camera with a 100 ASA film, put the camera on a tripod - and take some shots of an infinity scene as with lots of definition right to the edges. Then examine the negatives under a lupe.
Alternatvely you can use a ground-glass screen in the film-plane; set the shutter on "B"; the aperture at 3.5; and the focus on infinity. Examine the scene on the ground glass .. again with a lupe. By either method you will get your answers.
Hope this helps
Stuart Willis |
Markus
Tinkerer
Username: Markus
Post Number: 10
Registered: 08-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 18, 2007 - 10:28 am: |
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Thanks for the explanation. Indeed somebody had 'serviced' this camera before... for example, on one side panel it has the strap holder from a yashica mat.
Yesterday, I took some photos at f/3.5 of an infinity scene and figured out that the taking lens was focusing a bit past infinity, such that infinity was actually at the 60ft mark. The image that was actually focussed at infinity was sharp from edge to edge (I scanned it to get a good view at high magnification), so I guess I am happy with the lens alignment. Now I readjusted the focus knob and also the viewing lens and will be running another test roll. BTW, I fine tuned the focus of the taking lens using the backsighting method. I'll run another test roll, today, to see if all this worked. I don't want to put the new leatherette on before I am convinced that the focus alignment is as good as I can get it to be.
If I could now just figure out a way to get the tripod socket/latch cover not to wiggle. I know that this thing has a left handed thread but I cannot get it to loosen to perhaps shim it with a washer as described in the service manual.
- Markus |
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