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EF 50mm 1.8 stm stopped working PLEASE HELP


I was doing some deep cleaning with my lens and when I put the back panel back on and put it on my camera the aperture setting wouldn't change and it would even let me focus idk what I've done wrong. 



When you say "deep cleaning" do you mean you dismantled the lens to clean it, if so then you have probably dislodged or damaged an internal cable.

Please tell us what you mean by "deep cleaning". What did you clean it with?


What do you mean by "back panel"?  Do you mean the plastic insert in the rear lens mount?



Mike Sowsun

I was using the lens pens retractable brush and a water down glass cleaner with a soft cloth and yes the plastic inserts on the rear lens mount

There really is no reason to remove the plastic insert when cleaning the lens. It exposes the delicate electronic circuit board and connectors. My guess is that you may have damaged some of those electronics. 





Mike Sowsun

"...a water down glass cleaner..."


Not just a bad idea but a very bad idea.  Water anything and cameras/lenses are not a good thing. 

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


Unless you can see if you dislodged anything or let it alone for a long enough to see if it dries out, the cost of shipping alone will probably be more than a used 50mm f1.8 is worth to repair.

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


What were you doing, what conditions you were shooting in that required you to do a "deep cleaning" of your lens?

John Hoffman
Conway, NH

1D X Mark III, Many lenses, Pixma PRO-100, Pixma TR8620a, LR Classic

I did a photo shoot on the beach and the wind picked up so bad there was sand everywhere in all the bags and none of my lenses are Weather sealed

The area we were in the sand was very fine almost like powder
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