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Power Diaphragm Unit EF100/2.8


Hi guys,


After having issues with the aperture of the above lens I did some research to find out that this is a well known problem and I have changed the Power Diaphragm at the Canon shop.


Now I'm wondering if this is a problem that is bound to happen again? Or is this resolved now that the power diaphragm has been changed.


So is this a problem with the initially installed power diaphragm or is there also a change it happens with this new one?


Thanks for your reply.


Best regards




I read this forum pretty consistently, and it's the first time I've seen that issue raised. When there's a prevalent problem, like the circuit board failure on the 70D, we usually hear about it. I think I'd chalk it up to bad luck and not worry about it too much.

Philadelphia, Pennsylvania USA


Agree, don't "worry about it too much."

EOS 1DX and 1D Mk IV and several lenses!

I found that on other places on the web indeed. Not here on Canon.


So I didn't make this up  Smiley Happy


I got it fixed but then I was wondering if this was a recurring problem or not.  As I have another lense that is exactly the same and I was afraid that one was going to get the same issue.


Thanks for your input guys. Much appreciated



I used one for a few years and it never acted up or failed.  So there you go, just use it and forget it.

EOS 1DX and 1D Mk IV and several lenses!

I had this fail on my 24-105 IS. It cost me 350 to fix it. just rec'd it today...Good news it was fast turnaround (2 days to get there, NJ for maine) and a few days till they shipped and it arrived the next day...and cost less than a new my had terrible lens creep and that was fixed...


but somewhat frustrating to have to spend that much..seems to be a well known issue.....I only use it as a hobby, not professionally, generally staying in my closet, well packed in a backpack....and never in incelement weather or treated rough....


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