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Tinkerer
Username: Snappyz
Post Number: 1
Registered: 06-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, June 27, 2010 - 12:46 am: | 
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Hello all!
I recently acquired a Canon AV-1 as a gift. After discovering that first roll of film shot with the camera was almost blank, I found that at faster shutter speeds (1/125 and higher) the shutter curtain fails to open.
This problem is not seen at slower speeds and the curtain opens up just fine.
I hope someone can give me some insight or tips on this problem before I resort to sending my camera in for professional repair...
Thanks!
-Z |
Aphototaker
Tinkerer
Username: Aphototaker
Post Number: 214
Registered: 12-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, July 25, 2010 - 10:04 am: |
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It would help if you posted some example shots.
I am suspecting a shutter capping problem. This happens when the shutter spindles are stuck due to died lubricants or accumulated dust.
To test for it, remove the lens and open the back of the camera. Point the camera to a bright wall (or to a window with bright outdoors) and release the shutter at various speeds while looking through the back of the camera. If you don't see constant brightness across the frame at different speeds, your camera is suffering from shutter capping. As the shutter works, you will make out the darkness due to the shutters not exposing the frame properly. 1/1000 speeds take a while to get used to.
As you charge the camera by winding for the next frame, the shutters travel to the winding side of the camera. When the shutter is released, the first curtain travels from the winding side to the film cartridge (rewinding) side. After the duration of the shutter speed setting (1/60, 1/125, etc.), the second starts to travel. If the speed is low, longer than 1/60 s, then the first curtain would have traveled all the across the aperture before the second starts. For faster speeds, the second starts before the first one has cleared the aperture. So for higher speeds, a slit travels across the frame.
If the spindles are not free from dried lube or are dirty such that they have some friction, the first curtain may slow down and the second curtain may hit it prematurely. This is most pronounced at higher speeds because even a small amount of friction affects the curtains' speeds. At slower speeds (longer than 1/60), you may notice that the right hand side of your printed photos may be under exposed.
The solution is to clean the spindles. There are many instructions here on how to do it. Briefly, here is what I do:
1. Open the bottom and top of the camera and identify the spindles (they will appear as little pins in brass bushings).
2. Put a few tiny drops of naphtha on them.
3. Work the shutter a few times. Let that stay for several minutes (to allow it to evaporate).
4. Drop tiny drops (around 1mm drops) of a suitable lubricant on the spindles. Do not over oil! Then work the shutter several times at various speeds.
5. Check for capping against bright light with the lens off and back open.
So that was my brief description and diagnosis of the problem. More experienced people may of course add/correct this info.
Good luck. |
