RF 400 hood screw jammed

[David Eaton]

Hi everyone. I’m having an issue with the hood for my 400/2.8. The thumb screw that allows you to attach the hood to the lens has jammed. I’ve tried WD40 to no avail. There was no impact on the hood or screw area that I’m aware of. I don’t know if something broke inside the mechanism, or if somehow the screw jumped a thread. Has anyone had a similar issue with one of these big lens hoods? What’d you do? Thanks.

 

[Dave Williams]

I think the top of the screw flips off and you may find a screw there to release it. I have a spare set somewhere , it came in about half a dozen pieces.

I have just found all the pieces still in their individual plastic bags, The centre must come off at the top but how isn't apparent. There is a screw underneath but the whole mechanism looks difficult to assemble and there is every chance you might break the plastic plate that is the locking mechanism if you force it. You don't have much choice though.
Maybe ring Canon CPS?

 

[David Eaton]

I think the top of the screw flips off and you may find a screw there to release it. I have a spare set somewhere , it came in about half a dozen pieces.

I have just found all the pieces still in their individual plastic bags, The centre must come off at the top but how isn't apparent. There is a screw underneath but the whole mechanism looks difficult to assemble and there is every chance you might break the plastic plate that is the locking mechanism if you force it. You don't have much choice though.
Maybe ring Canon CPS?

Thanks. It is odd that there is no visible way that assembly connects, and I for don’t want to force it. I have contacted CPS and they’ve already sent a return label for me!