FDn lens aperture stuck - no f-stop beyond f 2.8

<p>This is my favorite 35mm FDn f2. The aperture ring will not turn past f 2.8, although it will open up to F2. When I activate the stop-down button on my F-1N, the aperture appears to be at f2.8, or f2. I put other FDn's on my F-1N and they function normally. Any of you experience this with an FDn lens?</p>

<p>Have you tested the lens in Speed priority? You need to mount the motor or the winder.<br>

If the aperture closes past 2.8 in this setting, you have a problem with the aperture ring mechanism, not with the cams or the aperture itself.<br>

Anyway, you will end up opening the lens, but it helps to know where the problem is located. If it is the aperture ring, opening on the mount side will give you access to the problem area; if the aperture itself has a problem, I think you should access through the front (not absolutely sure here, but from experience on other lenses, it is usually the case).</p>

<p>Is the lens a bayonet mount or is it the collar type? I have 50mm ƒ1.4 lens that I just discovered does not stop down at all, no matter where the ring is set. It is the collar type. I have a 50mm ƒ1.8 that is the bayonet type. On the collar type, look at the back of the lens, on the top there is a pin, if you depress it with the tip of a pen you can rotate the collar. This will free up the one lever on the back of the lens to stop it down. Now try and turn the aperture, does it still stop at ƒ2.8? With it at ƒ2.8, can you move the lever and stop the lens down? Also look at the two levers, are either of them bent, is it possible the lens was dropped?</p>