Canon FD 28mm f/2.8 Aperture blade problem? : LUSENET : Canon FD : One Thread

Hello everyone,

When I put my Canon FD 28mm f/2.8 lens on my Canon FT QL and push the stop down metering lever, nothing seems to happen, despite changing the aperture setting on the lens. This does not happen with my 50mm lens so I guessed that the aperture blades are stuck together. Is this correct? And also, is there a way for me to open up the lens and unglue the aperture blades without destroying the lens? If it is possible, I would like to fix this problem myself instead of giving it to a repairman.

Thank you all so much!

-- Eric Shen (, September 25, 2001


Do you have the new FD type or the older kind with the silver mounting ring? The older one is easier to work on but is still difficult to describe without pictures. You will need jeweller's screwdrivers, a spanner, a rubber sheet and cup to remove the front shield as well as a clean place to work. Look for volumes 1 & 2 of Tomosy's books "Camera Repair" for some general guidelines. I don't recall anything specifically on Canon lenses but you should get the general idea.

Now having said that, if it's only one lens it will probably be cheaper to take it or send it to someone with some experience at this. Hopefully it shouldn't be more than $50.

Good luck & cheers,


-- Duane k (, September 25, 2001.


Duane is absolutely right. I'll add that I've done this job on both the older breechlock (silver ring) and newer mount 50mm lenses. These can be done without a spanner wrench, but both 28mm lenses appear to need one. In the 50mm's, the diaphragm unit was actually easier to service in the new mount lens, since it was removable as a unit. The older lens uses part of the lens barrel to hold the leaves in place...reassembly was a bit tedious! The newer lens has plastic blades instead of aluminum. I was worried about creasing the aluminum blades. In both the 50mm lenses, the diaphragm came out the front.

It can be done, with adequate tools, a steady hand, and a good memory for remembering where all the pieces go. Good luck!

-- Alan Swartz (, September 25, 2001.

If you try this yourself, get a camcorder and mount it so that it records how you took the lens apart. Then you can see how to put it back together.

-- David Presson (, September 27, 2001.

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