# AE-1 Program Diaphragm stop-down issue



## 17thCavalry (May 30, 2018)

I have an otherwise exceptionally well preserved AE-1 Program 35mm SLR that I recently purchased.  The camera, while used, is in near mint condition, although it does not properly close the lens diaphragm (whether in "Program Mode" or stop-down mode) consistently upon pressing the shutter release. 
I own other Canon 35mm film SLRs that accept Canon FD lenses, and the lenses all function correctly on those when I swap them around, so the lenses are not the guilty party. 
I have to conclude from this that there must be something "hanging up" in the guts of the camera body.
Has anyone else out there experienced this?  Is there a "home remedy" or am I looking at getting a professional repair done?  I really like this AE-1 and my A-1, so I want the AE-1 to work like when it was new out of the box.  Any ideas what to do?


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## TCampbell (May 31, 2018)

As I recall (it's been a few years).

#1 Camera must have it's battery installed (it's a small 6v battery.  They were traditionally silver-oxide batteries but you can now get them as lithium batteries... that's fine as long as the size and voltage are correct.  But if you do need to replace it, DO NOT use an "alkaline" battery because those batteries leaks they deplete and age.... and that'll just be a mess).

#2  You just "wind" the shutter so it's ready for the next shot (the DoF preview wont work if the camera isn't ready to shoot).

#3  Make sure the lens is fully locked in (seated).  The aperture blades are controlled by mechanical levers that wont interface correctly if the lens isn't properly attached.

#4  Rotate the aperture ring to the f-stop you plan to use (if it's in the "A" position then the camera will pick the f-stop.  Come to think of it... i'm not sure you can use DoF preview in auto-aperture mode)

#5  Slide the DoF preview switch and the aperture blades should stop down.


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## sniper x (Jul 30, 2018)

Please explain what you mean by "does not properly close the lens diaphragm"...Do you mean the lens doesn't appear to stop down to the correct aperture? What shooting mode are you using and what lens and shutter setting are you using to test this?
I'd suggest (if you have not tried this already" Setting the camera to manual mode. Set the shutter to say 1 second. Set the aperture minimum or the smallest it'll go. Cock the camera with a fresh batt in it and press the DOF preview button over and lake sure it locks.


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## 17thCavalry (Jul 30, 2018)

sniper x said:


> Please explain what you mean by "does not properly close the lens diaphragm"...Do you mean the lens doesn't appear to stop down to the correct aperture? What shooting mode are you using and what lens and shutter setting are you using to test this?
> I'd suggest (if you have not tried this already" Setting the camera to manual mode. Set the shutter to say 1 second. Set the aperture minimum or the smallest it'll go. Cock the camera with a fresh batt in it and press the DOF preview button over and lake sure it locks.


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## 17thCavalry (Jul 30, 2018)

Well, I mean just exactly that...…..the lens does not seem to close down consistently to the pre-set "f" stop in, say, manual mode.  Since this is the case, I am suspicious  of what will happen in the "Program" mode.  I have the user manual for this device, so after studying that and doing everything it prescribes to do, I'm still not convinced I have either:
a) figured out how the camera is supposed to work, even though I have other Canon AE-1's and A-1's, as well as NIKONS, LEICAS, etc...……or.....
b) Maybe I need to have an experienced technician probe it's guts...…

Look, thank you for your reply and obvious interest.  That is what makes these forum sites so useful.  When I have come up with a fix, regardless of what it is, I will post the outcome.

Thanks, once again...……

Frank


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## sniper x (Aug 14, 2018)

Have you tried to use the DOF preview lever while it is cocked and has a good battery? I mean to look and see if the aperture looks correct...


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## compur (Aug 22, 2018)

This is a pretty common bug with the AE-1/AE-1 Prgm cameras. I see it from time to time on cameras I find. As far as I know the solution is not easily done and too expensive to send in for repair.

IMO, the Canon A-series cameras have just about reached the end of their lifespan and are often found with various problems (or completely dead) nowadays. Even the ones that look mint. If you like FD lenses I would suggest getting a nice FTb or F-1 instead. (Forget the T-series -- they're even worse than the As).

Or, the Nikon FE/FM series cameras are much more reliable than Canon A-series, especially the FM/FM2 models.


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