Fixing FDn 100mm f/2.8. Stuck and I need help!

Hey guys,

Well after feeling bold and fixing the lens mount on my T90 I thought "Gee it can't be that much more difficult to do the same for my wobbly 100mm."

Well, it turns out I was wrong. I'm stuck and not sure how to proceed.

Basically the issue with my lens was that the lens mount was quite wobbly and I could shift the lens in any direction while it was mounted on a camera.

I removed the screws holding the rear mount and carefully removed the full thing. I found the loose screws and tightened them with a PH00 screwdriver.

I ran into trouble when trying to put the mount back into place as I'm not sure how things are supposed to be. I eventually did get it rebuilt but I lost control of the aperture. It was stuck wide open.

Does anyone know how to re-assemble FD lenses that can guide me through this?

Thanks!

- Abram


Here are photos showing where I'm stuck. I'm not sure how to properly align these things so the lens retains control of the aperture lever.

Photo Feb 18, 10 37 21 PM by Abram Goglanian, on Flickr

Photo Feb 18, 10 36 41 PM by Abram Goglanian, on Flickr

Photo Feb 18, 10 36 19 PM by Abram Goglanian, on Flickr

Hi Abram,
On the last photo, there is a lever to the right of your pointer, just past the black screw. As I remember this should be spring loaded. When you look at the inside of the mount assy. There is a lever with a rectangular notch in it. The fork slips over the tab and the mount is rotated until the screw holes align. Insert screws & tighten.
You may have to fiddle about a bit.

Yes I have looked inside and noticed that mechanism is controlling the aperture as it should be. I am not sure however how the "sliding grey ring" (sorry I don't know what it is called) is out of position.
When I re assemble the lens all looks correct but as soon as I mount it to a camera or lens adapter I lose aperture control.

I know I'm clearly doing a step wrong I just am not sure what that step is.

If the ring is not engaged with the prong, it will only fully stop down. Sometimes it takes several tries to get them properly engaged.
I can be a little frustrating.
You may have to hold the stop down lever on the back of the mount to one side to align it.

I don't know guys... I have tried every conceivable option and every single time I re-assemble the lens I lose aperture control. I just don't understand what I'm doing wrong. I've carefully looked at all the parts and I just cannot seem to figure out what is going wrong. All I know is that as soon as I mount it on the camera, the mount shifts and screws everything up. There is nothing loose, nothing left to tighten so I cannot figure out why this is happening.