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Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 34
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 21, 2009 - 05:36 pm: | 
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I just purchased a Canon AE-1 in order to get the lens it was attached to. The camera appears to work fine. The meter and shutter speeds are accurate. The film transport area is clean. But when I watch the lens stop down actuation lever (the one that uncovers the red dot), I notice that its movement is erratic. Sometmes it moves, uncovering the red dot, sometimes it just quivers a bit. When I push in the stop down button for stop down metering, it moves to the left just like it's supposed to do.
But when I mount a lens and trip the shutter, it stops down the lens properly during exposure. Every time.
I double checked it against my F-1, and my F-1 works the way I've remembered Canon FD cameras always to work, namely unless the stop down button is pushed in, which pushes the lever over, the lever always is activated for the time duration of the selected shutter speed.
So, I'm wondering, why the erratic operation, and why does it appear to be behaving properly once a lens is mounted? Puzzling. |
Ronnies
Tinkerer
Username: Ronnies
Post Number: 5
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 24, 2009 - 03:39 am: |
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Canon FD aperture mechanisms need the breech lock ring or the whole lens (for the later models) in the 'mounted' position. If the lens is just held in the normal dismounted position the aperture doesn't work as normal.
Ronnie |
Glenn
Tinkerer
Username: Glenn
Post Number: 705
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 24, 2009 - 08:41 am: |
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Michael,
Ronnie's comments obviously refer to the FD lenses when dismounted. Your observed 'problem' is in fact a normal consequence of operating the AE-1 without a lens attached. The metering circuit is trying to set an aperture and also detect the max aperture of the 'attached' optic. With nothing attached, the electronics/mechanism cannot complete the detection sequences - hence the 'quiver'. The actual movement of the actuating lever under these circumstances appears to be influenced by the amount of light entering the open mirror box, and hence reaching the sensor.
To quote a rather annoying UK TV advert - 'Simples!'. |
Ronnies
Tinkerer
Username: Ronnies
Post Number: 7
Registered: 09-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, October 24, 2009 - 02:29 pm: |
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Ok. My bad.
Sorry. I misread it as a lens stop down problem.
But surely the camera will think it's in manual mode since the little pin won't be pushed into the mount and so should push the lever all the way across? Or is that not how it works?
Ronnie |
Cooltouch
Tinkerer
Username: Cooltouch
Post Number: 36
Registered: 01-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, October 28, 2009 - 11:57 am: |
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Thanks, Glen! I wondered about this, but reasoned that with the lens dismounted, the camera was effectively in manual mode and would just act as such. Anyway, good to know. Now I can sell the camera with a clear conscience. Probably be lucky if I get 20 bucks for it.  (Nope, don't want to keep it, already have another AE-1 anyway) |
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