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Pigeon_sandwich
Tinkerer
Username: Pigeon_sandwich
Post Number: 1
Registered: 03-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 11, 2009 - 04:29 am: | 
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I just received a fairly nice looking Yashica 635 (Yashikor lens) from eBay. I tested all shutter speeds and they seemed fine, although the slower speeds were erratic.
Then I tested the 1 sec speed again, and the shutter became stuck open. I haven't tried re-cocking the shutter or anything. I've tried giving it a shake, tapped on the shutter assembly, wiggled the lever, etc. The taking lens also has a small speck of fungus. What should I do with it (other than get rid of it)?
I'm prepared to try cleaning the internals myself. Or if this is really complex, I'll consider sending it to Mark Hama (I'm in Australia). If somebody could give me some instructions, I'd be hugely grateful.
Thanks in advance |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 833
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, March 11, 2009 - 05:05 am: |
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The shutter blades and/or escapement are dirty and sticky. To clean them, you have to remove the front fascia panel, which in a Yashica unfortunately involves losing the brittle leatherette because it won't survive removal; then you unscrew the front lens cell, then remove the front panel from the shutter. I have some general notes here, which don't deal specifically with the Yashica but show you something of what the job is like:
http://rick_oleson.tripod.com/index-158.html
http://rick_oleson.tripod.com/index-55.html
http://rick_oleson.tripod.com/leaf_shutter_cla.htm
http://rick_oleson.tripod.com/index-88.html |
Pigeon_sandwich
Tinkerer
Username: Pigeon_sandwich
Post Number: 2
Registered: 03-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 13, 2009 - 08:48 am: |
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Thanks for the info, Rick. I left the camera in the sun on the seat of my car, while I was at work. When I came back it was warmed up, I jiggled the shutter cocking lever a bit and it clicked shut again! The faster shutter speeds still sound good. So now, at least I can try running a film through it.
It appears, from looking through the viewfinder, that it doesn't focus to infinity. With the focus dial set at infinity, the viewing lens is focused to about 2 metres. I don't know if the taking lens is also incorrectly focused. I will find out when I get the first film processed.
I think I will order some replacement leatherette, as I'll probably give it a clean eventually anyway. Thanks again. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 836
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, March 13, 2009 - 05:30 pm: |
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Personally, unless you've already got it loaded, I wouldn't waste the cost of film and processing on it right now. Odds of the focus being off are great, and there's a good chance that the shutter will hang on you again before the roll is finished. I'd clean the shutter and set the focus straight, and then load it up. |
Pigeon_sandwich
Tinkerer
Username: Pigeon_sandwich
Post Number: 3
Registered: 03-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 19, 2009 - 04:24 am: |
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Well, I had it processed. Based on my guessed exposures, the shutter is working well. The fungus in the taking lens had no noticeable effect, despite being a fairly dense, yet small spot.
Turns out the taking lens is fairly accurately matched to the viewing lens in terms of focus. The only remaining problem is that neither of them focus to infinity. I tested it with a homemade ground glass (rather ground plastic) screen on the film plane. Is this difficult to calibrate? If it requires taking off the focus knob, I think I'll just take it to a shop, since I don't have the right tools.
Cheers |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 839
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 19, 2009 - 04:50 pm: |
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In most TLRs of this type, the face of the focus knob unscrews, revealing a nut on a threaded shaft inside the knob. You should be able to loosen this nut, reposition the focus knob and clamp it all down again. |
Late_starter
Tinkerer
Username: Late_starter
Post Number: 1
Registered: 03-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, March 30, 2009 - 09:05 pm: |
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Hello,
I have been getting used to a Yashica 635 for a little while, having just got back into photography after waiting 35 years. I love the big negatives, but I decided my camera is over exposing slightly, so I thought of a way to test it. I found out an ordinary light emitting diode makes a good photo diode, so I hooked one up to my scope, and shined a bright light through the lens, exposing the diode. Voila, there is my exposure time on the scope. Yup, sure enough 1/500 is actually about 1/300, and all the other settings are multiples as they should be. I am going to use some of the excellent information here on this forum to fix it. Thanks for the help guys, any explicit suggestions?
Best regards,
Late_starter |
John_shriver
Tinkerer
Username: John_shriver
Post Number: 42
Registered: 12-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, March 31, 2009 - 07:41 pm: |
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Late_starter: I'd expect 1/500 to really be 1/300 on a leaf shutter. The highest shutter speed is often optimistic. Also, the high shutter speeds are only accurate at wide apertures, otherwise shutter efficiency gives you longer than expected exposures at small apertures.
If the rest of the speeds are accurate, it's accurate. You could clean it, and perhaps the leaves if they are dirty, but don't remove the slow-speed gear train, as it's position is how the shutter speeds are calibrated. |
Late_starter
Tinkerer
Username: Late_starter
Post Number: 2
Registered: 03-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 02, 2009 - 07:20 pm: |
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John,
Thanks for the advice, but I already started the process using Rick's links for moral support. The clockworks are modularized, and come out for cleaning easily. They re-install with a couple of screws and no provision for adjustment is evident. Using my scope, the results are fantastic. The low speeds are right on, they were varying all over the place before. I see what you mean about the highest speed. The time that the leaves are opening and closing is a big part of the total time open. So...it depends on the f stop...and my scope can't integrate under the curve. But if you squint a little, it looks about like 1/500 of a second. I appreciate the help, now to take more pictures.
Best regards |
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