This is an EF 24-105 lens which we received from a customer completely dismantled as pictured. The lens required a new aperture flex and the customer was tempted by the internet DIY option. You can see the new flex he bought from the internet in the front of the picture.
This flex is not to Canon spec and is missing the important non reflective coating.
It’s just as well we know where every screw, washer, shim and guide belongs!
Here is the lens after we replaced the aperture unit, cleaned and reassembled.
The lens then had a full optical set up and is now back to how it should be.
Not the job for a DIY project.