| Author |
Message |
    
Deegee
Tinkerer
Username: Deegee
Post Number: 1
Registered: 01-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 20, 2010 - 08:28 pm: | 
|
Hello everyone,
I'm new to the site/forum and new to folding camera's so please bear with me if I'm not using the camera/forum correctly...
Right, I bought an Agfa Billy Record Jgestar 7.7 (ebay, where else) checked that the bellows were light tight and that the shutter fired ok. Both seemed fine (apart from the bulb setting which was bit sticky) so took the camera on holiday and shot a couple of rolls of film. The results were really disappointing. All pictures on various distance/aperture/shutter speed settings are not really sharp but with a noticeable increase in sharpness on the righthand side of the image. see this flickr link for an example;
http://www.flickr.com/photos/45458521@N00/4076217004/sizes/o/in/photostream/
or
http://www.flickr.com/photos/45458521@N00/4075464325/sizes/o/in/photostream/
I am led to believe that the poor focus on Agfa's can be down to stuck elements of the lens, from the grease drying and sticking over time. However when I move the distance focus lever the front dial/element seems to move the same sort of degree's movement (approx 30degrees) and comes forward in a helical movement as I'd expect it to.
The only thing I can see that doesn't look right is that if I look down over the camera from above the lensboard (by this I mean the part with the lens/shutter/timer etc) is slightly not parallel to the body of the camera. Not by a great amount, only 2mm or so, just enough (to imagine?) it's apparant to the naked eye?
Basically is this likely to be the problem and is there a common/standard fix to help the lensboard assume a correct position, as there doesn't seem to be any really bad/obvious damage to the camera.
Thanks in anticipation of your views/help.
Cheers
Dave |
David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 73
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 20, 2010 - 10:39 pm: |
|
Your sharpness problem is undoubtedly due to the lensboard not being parallel to the film plane, not to any helical lubrication (or lack thereof) problems. As you guessed, the focus mechanism moves the lens forward and backward linearly.
You may have to bend things to bring the lensboard back into parallel; after all, this is probably how it got out of whack in the first place. |
Deegee
Tinkerer
Username: Deegee
Post Number: 2
Registered: 01-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 21, 2010 - 05:24 pm: |
|
David, thanks for your reply. I was trying to experiment with moving the lens board into a parallel position with a piece of tracing paper held across the film gate and find that when the tracing paper bowed outwards (away from lens/towards me) the image (lens open on B setting at max aperture) suddenly became sharper. Which would seem as if the lens is trying to focus about 5-10mm further back from the film plane, any ideas? |
David_nebenzahl
Tinkerer
Username: David_nebenzahl
Post Number: 75
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, January 21, 2010 - 07:53 pm: |
|
Two problems here, as you're probably figured out:
1. Lens not parallel to film plane
2. Lens not in proper focus
You need to fix 1) before you tackle 2).
Once the lens standard is straightened out and the lens is parallel to the film (you can probably determine this by careful visual examination), you can tackle any potential focus issues. Hopefully, straightening out the lens standard will make the lens focus where the factory set it, without any further monkeying around necessary.
To check the focus, instead of paper, get a proper piece of ground glass to act as a view screen at the film plane. (You can easily make this yourself; I'll be happy to give you instructions if you like.) Then you can focus the camera on something at infinity and see if the image is sharp. If it isn't, then it's a matter of shimming the lens off the lensboard if it's too close, or else bending parts if it's too far away. Obviously much easier if the lens is too close. (I don't know this camera, but it's possible there may be some adjustment possible within the lens assembly. Perhaps others can confirm this.)
You're basically collimating the lens without a collimator. Of course, if you have access to a collimator, that's a much more accurate method of establishing proper focus.
Good luck, and, as always, try to have fun with it. |
|
