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Vincebodie
Tinkerer
Username: Vincebodie
Post Number: 1
Registered: 02-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 13, 2012 - 12:41 am: | 
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Hi, it's my first post, woohoo!
(and certainly not my last I'm sure)
So I have an A-1 that I love dearly, and I've been picking up several lenses for it to complement the ones that it came with when I bought it in a bitchin red felt lined case with all kinds of cool compartments (all of which I bought for a price that will make many of you not want to reply out of jealousy, so I won't mention it, haha).
Anyhow, the lenses it works fine with are:
Canon FD 50/1.8
Kalimar MC 28/2.8
Vivitar 28/2.8 auto wide angle
Canon FD 70-150/4.5 zoom
The ones it jams with are:
Tamron Adaptall 28-70/3.5-4.5
Vivitar Close Focusing Auto Zoom 100-300/5
I've noticed the auto aperture levers on the last two are more resistant than the others, especially the Vivitar 100-300. I'm guessing that's what is causing the jamming. I can shoot fine with either lens in full stop down mode.
QUESTION: Will a drop of lubricant in just the right spot free up these levers? Or do I just have a low battery perhaps? These lenses have worked before, though not consistently. |
Thepurush
Tinkerer
Username: Thepurush
Post Number: 13
Registered: 01-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 13, 2012 - 08:06 am: |
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Set aperture to minimum(f 16 or f11). Operate camera in B mode looking in to the lense from the front of camera. I the aperture fails to close, it maeans the aperture blades are stuck. My be the oil in the pins has spread across the blades and the blades no longer move freely. I tha is the case ther is only one way out. Clean the blades. Requires extensive dismantling. |
Vincebodie
Tinkerer
Username: Vincebodie
Post Number: 2
Registered: 02-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 13, 2012 - 10:03 am: |
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But of course... does that explain why the lens will work sometimes, depending on temperature/humidity?
By the way, the Tamron is now working after I noticed that the auto aperture lever was slightly bent, causing drag. Straightening it out fixed it. |
Vincebodie
Tinkerer
Username: Vincebodie
Post Number: 3
Registered: 02-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 13, 2012 - 09:59 pm: |
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So it fails the B mode test. What's wierd though is that operating the lever by hand, the blades move smoothly back and forth. It seems like the return spring on this lens is just stronger than on the others, causing greater operating resistance.
Is it possible the battery has anything to do with it? It's been a while since I replaced it, though the indicator still lights up brightly and everything else works fine. |
Thepurush
Tinkerer
Username: Thepurush
Post Number: 15
Registered: 01-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 14, 2012 - 06:25 am: |
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Cannon lense aperture operates differently compared to other lenses.Thye are normally open type. If it failed B mode test then the reason is cleaar. Did you try to operate manually as fast as the camera does? May be the blades do move much slowly due to friction. Remember it is friction due to oil between blades not dirt. |
Thepurush
Tinkerer
Username: Thepurush
Post Number: 16
Registered: 01-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 15, 2012 - 10:09 am: |
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If you are sure that blades are OK, then the problem could be with in the camera. The lever which closes diaphragm often becomes hard and fails to apply required force on lens. It just needs a small drop of oil in it fulcrum. Wait for few hours for oil to spread then test. Non usage is the cause of such problem and it is quite common. |
Vincebodie
Tinkerer
Username: Vincebodie
Post Number: 4
Registered: 02-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, February 20, 2012 - 10:21 pm: |
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I will look into oiling that fulcrum.
A new battery got it working again with all lenses and even the 300 with a doubler. Apparently there is a correlation between a low battery and the lock up issue, starting with lenses with more spring tension like this one.
It's definitely not blade drag. The rebound is much too "snappy" for that.
Thanks |
Glenn
Tinkerer
Username: Glenn
Post Number: 970
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, February 21, 2012 - 07:39 am: |
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Always suspect the battery when the A-1 displays erratic lens operation, especially with none OEM longer focal length and 'adapt to all' zoom lenses. Also, do not go and start oiling the odd internal part on a whim - a partial seizure in any part of the mechanism indicates that the camera requires a total clean and relube.
The only portion of the A-1 mechanism that benefits from a minute drop of oil, as and when the symptoms occur, is the mirror damper. The infamous 'Canon Screech' is due to wear in the inertia flywheel bushing and if one keeps a layer of oil on the shaft, the flywheel will not vibrate/oscillate when it rotates at speed as the mirror flips. |
