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Harlee
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 02, 2005 - 01:58 pm: | 
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I inheirted a Yashica GSN with focusing problems. It was way off on infinity. I set up a focusing chart at a measured 10 feet, placed a ground glass on the film plane, set the distance marker on the lens to 10 feet, and turned the adjusting screw [under the hot shoe], till the lens was focused at 10 feet. But when I ran a roll through it it came out blurred. Repeated the procedure, only setting the lens to infinity, but the adjusting screw cam can turn 360 degrees and the superimposed images will not line up. I can get them close, but not right on. It also appears to be off vertically as well as horizontally. Which is the vertical adjusting screw under the top cover? Has something been jarred to knock the horizontal images off so that they will not line up at infinity. I'm wondering that if I can get the images close at infinity, will the vertical adjustment fine tune the images to line them up? Perplexed! |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 03, 2005 - 05:21 am: |
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In your case you first should check whether the lens itself is properly focussed. There are several methods to do so, I prefer the 'backsighting' method with a hair stretched across the film screen and an additional SLR with split image indicator. You have to set the mode ring to B and fire the shutter. The battery current consumption is rather high in this mode but that's what you have to pay... Loosen the set screws around the focussing ring and turn it until it is set to oo when the lens is in proper oo focus.
I am sure your rangefinder can be adjusted properly after proper adjustment of the lens. In any case you should do the vertical alignment first. If I am not mistaken this is done via a tiny screw on the bottom of the rightmost mirror (the smallest one on a socket, seen from the rear). |
Harlee
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, January 03, 2005 - 06:53 pm: |
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I'm a little confused - where does the second slr with the split image indicator come into play? Perhaps I'm a little thick; if I loosen the screws on the focusing ring and turn it till it is set to OO [infinity I'm assuming] how does this focus the lens? I'm not sure what I'm supposed to be looking for - am I trying to get the hair on the film plane to come into focus? Befuddled! |
Winfried
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 04, 2005 - 03:14 am: |
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You will find a description of the focus check method here:
https://kyp.hauslendale.com/classics/collimator.html
If the lens does not focus to oo, loosen the focus ring, turn it a bit backwards, tighten it and try again. If the lens is in focus now at a certain position of the focus ring, DO NOT turn the focus ring any more while it is tightened. Loosen it again and turn it against the oo stop. |
Harlee
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 04, 2005 - 04:56 am: |
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Thanks Winfried, I appreciate your help. I printed off the sheet on "rangefinderforum" and will try that method later today. Have a great 2005! |
