Canon FD certain apertures stuck

[plantednoob]

Hi everyone. I have a 50 mm 1.4 lens breech mount that won't go past f4 when mounted. From f1.4-4 I can see the aperture narrowing but after that it won't narrow down further. When I dismount the lens and disengage the lock pin it does fully go through 1.4-16 with no problem whatsoever. Any thoughts? Can anyone point me in the right direction?

[jim_bielecki1]

So it won't stop down beyond F4 when mounted on a camera? Which camera are you using?

[plantednoob]

So it won't stop down beyond F4 when mounted on a camera? Which camera are you using?

Exactly. I'm using a canon AE-1

[cmuseum]

that won't go past f4 when mounted.

 

How do you test that? By pressing the stop down button and turning the aperture ring tof/5.6, f/8 etc? Or by chosing a slow speed or bright scene that would require the camera to use f/5.6 or smaller?

[plantednoob]

How do you test that? By pressing the stop down button and turning the aperture ring tof/5.6, f/8 etc? Or by chosing a slow speed or bright scene that would require the camera to use f/5.6 or smaller?

I'm pressing the stop down button and turning the aperture ring.

[jim_bielecki1]

What happens when you put the lens on "A," pick a slow shutter speed, and press the shutter? Does the lens stop down to a small F-stop then? Do you have another lens you can put on your camera? If so, put that on and see what happens. I'm trying to figure out if the problem is with the camera, or the lens.

[cmuseum]

Possibly something is obstructing the aperture simulator lever when the lens is mounted to the camera. The aperture simulator lever is the smaller of the two levers at the rear of the lens, located at left-hand side when viewed from the rear.

 

This is what I would check next:

1. Is anything inside the camera obviously obstructing the travel of the lever?
   
2. Does the camera's aperture signal lever move freely?
   

The aperture signal lever is the one moving vertically at the right-hand side inside the camera mount:

 

 

1. Remove the lens.
   
2. Cock the camera.
   
3. Engage the stop down button.
   
4. Gently push the lever towards the bottom of the camera.
   

 

 

There should be even and only light resistance along the lever's entire travel.

[plantednoob]

Possibly something is obstructing the aperture simulator lever when the lens is mounted to the camera. The aperture simulator lever is the smaller of the two levers at the rear of the lens, located at left-hand side when viewed from the rear.

 

This is what I would check next:

1. Is anything inside the camera obviously obstructing the travel of the lever?
   
2. Does the camera's aperture signal lever move freely?
   

The aperture signal lever is the one moving vertically at the right-hand side inside the camera mount:

 

[ATTACH]1283674[/ATTACH]

 

1. Remove the lens.
   
2. Cock the camera.
   
3. Engage the stop down button.
   
4. Gently push the lever towards the bottom of the camera.
   

 

[ATTACH]1283675[/ATTACH]

 

There should be even and only light resistance along the lever's entire travel.

Thank you so much for taking the time to answer my question, I was able to get it fixed! Really appreciate the help from everyone on here :)

[David Archer]

I have exactly the same problem. How did you get this fixed?

[RickLaRock]

I have exactly the same problem. How did you get this fixed?