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Jamie MacQuarrie
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Votes: 0 (Vote!) | | Posted on Monday, February 27, 2006 - 11:36 pm: | 
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It sounds like a few people have had problems with their Konica shutters. Has anyone encountered the problem of the shutter staying open too long or sticking when shooting in cold weather? I've wasted a lot of film because of this happening. I'm wondering if it is a simple solution to clean the shutter yourself or if you need an experienced but expensive professional at a camera store to do it for you.
Thanks |
Jamie MacQuarrie
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Votes: 0 (Vote!) | | Posted on Tuesday, February 28, 2006 - 12:17 am: |
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As an aditional note to the above problem, the reflex mirror is also slow to return to it's position sometimes and when advancing the frame a shot sometimes fires off on it's own. These problems only occur when a lens is on the camera. These problems don't just seem to happen in cold temperatures after all as I've just checked the camera and the problems occur also at room temperature. Does the whole thing need to be opened up and cleaned well? |
M Currie
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Votes: 0 (Vote!) | | Posted on Tuesday, February 28, 2006 - 08:34 am: |
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Just curious, have you tested this with more than one lens? If it only happens with a lens on the camera, the problem might be in the aperture mechanism of the lens itself. That mechanism is spring-loaded, and in the viewing state the camera's lever holds it open against a spring. When the shutter is actuated, the lever in the camera moves out of the way, and the lens's spring closes its aperture to its correct setting. It should stop down pretty quickly, but if the lens is sticky, it won't, and when the shutter has completed its job, and the mirror starts back down, the camera's aperture lever must now push the lens's aperture open against the internal spring pressure, as well as any stickiness, so it might be hanging up on the return trip.
If the problem is in the shutter, which is a vertical type, you should be seeing exposure errors in horizontal bands of either light or dark.
If the aperture of the lens is sticking (remember it is only internal spring pressure in the lens which stops it down during exposure), I'd expect to see either overall bad exposure, or less defined vertical banding. And of course, if the camera is at fault, you can expect the problem to occur with or without a lens.
Here's something to try. Take the lens off the camera, and open the back. Look through the camera from behind, at a comfortable distance. Now repeatedly fire the shutter, especially at any speeds which you think might be the problematic ones. When the shutter works right, you'll see the entire rectangular area as a bright hole. If it's erratic, that area will change in size. Just keep firing, and if there's a problem, you'll start to notice it. If it doesn't misbehave after a couple of dozen firings, I think you can assume the problem is in the lens.
OK, I just took a look at my T3, and in the interest of science, I put the shutter on "B" and fired it. I took a pencil and used it to prevent the aperture lever from returning fully, as might happen with a sticky lens. When it was held back completely, the camera would not wind or cock, but when it was about 80 percent back, the camera wound, but immediately fired the shutter without pressing the button!
Definitely, check that lens. |
Jamie MacQuarrie
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Votes: 0 (Vote!) | | Posted on Tuesday, February 28, 2006 - 04:35 pm: |
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Thank for your post. I have checked the lenses already and the problems seem to only happen with my two out of three of my lenses, and don't occur without any lens at all. The problems occurred quite frequently last night when I checked my camera, but today It seems fine. Today the shutter only missfired once when the frame was being advanced. It seems all the playing around with it and firing it off dozens of times has had some effect, but I'm sure it's only temporary. Maybe the camera can't sit for so long without use. I had a feeling the problem was in relation to the lenses but what can I do about it? Is there anything you can do to the lens? Is this a common problem in T3's?
Thank you for your help. |
M Currie
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Votes: 0 (Vote!) | | Posted on Tuesday, February 28, 2006 - 09:59 pm: |
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I have not heard of sticky lenses being a special problem in Konicas, though I have heard that the T3 shutter can go awry, so I can't really give much advice on that. I have found in general that camera shutters like a little regular exercise, but of course if you have film in it that can be kind of expensive.
Looking a little closer at my T3, I see I've made a mistake in my previous hasty observation. The aperture actuating mechanism has a pretty powerful spring which returns it to the full-open viewing position after the shutter fires. If you take off the lens and put the shutter on "B" you can see that when you push the button, the main aperture actuating lever in the camera (near bottom black leveer with end bent downward) moves to the left, followed by a ring whose tab contacts it. This ring is what actually contacts the lever in the lens. This ring is, I think, the part which the AE system traps to control the aperture in auto exposure mode. The spring which causes the ring to follow the lever is pretty weak. You can hold it back easily. It need not be strong, because the lens's aperture lever has a spring which pushes that way too. If you hold the shutter button down, you'll see that the ring can be moved back and forth pretty easily. But when you release the button, the lever in the camera has a pretty strong spring which pushes it back to the wide-open, viewing position, against the action of the weak spring in the AE ring and the spring in the lens. It looks as if it would have to be a very sticky lens indeed to fight that spring. A bent or binding AE ring or a problem in the associated mechanism would seem more likely.
One thing you might do is to hold the shutter open at "B" and see how freely that ring moves back and forth. You should feel some mechanical resistance, as it engages whatever mechanisms it deals with, but it should move fairly smoothly, and when you let go it should return (though lazily)in the clockwise direction. When you let go of the button it should return all the way quickly.
By the way, since I may not be using the correct terminology, just to keep it straight, I'll run through the parts. We're looking at the camera with lens off, oriented as we face the front. You'll see two little black levers in a slot near the bottom. The lower one, with its end bent down, is what I'm calling the aperture lever, the one with the powerful return spring. The ring I'm referring to as the "AE" ring has a tab sticking up which ends up between the lens's aperture lever and the camera's. The lens's aperture lever rests against the right edge of the tab and the pin on the back of the tab rests against the right edge of the camera's aperture lever. This ring goes all around the inside of the mounting flange, and connects to the internal mechanism of the camera with a pair of claws at approximately 9:00 and 3:00 positions. The other black lever in the lower slot, with its end bent up, is the indexing lever. A tab on the back of the lens bears on this, to tell the meter what kind of lens is on and set the max aperture flag in the viewfinder. At about 2:00 on the flange, just below the red dot, is another little spring-loaded tab which tells the camera when the aperture ring is locked into the "EE" position. It's engaged by a little boss on the back side of the lens's aperture ring.
One other thing I notice on mine is that the AE ring's tab contacts the aperture lever with a pin on its back side. There is very little clearance behind that pin, and I imagine if it got bent or pushed in at all, it could bind. |
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