harcosparky wrote in post #10928397
If you had known they were in there ahead of time, do you think you would have been able to prevent the loss?
Did you have any information from Canon as far as disassembly instructions.
A previous poster mentioned needing a 'clean room' and he is right, opening up a lens in a room in your house could put more dust inside then you can clean out. At the very least I would not try it without an excellent laminar flow hood with some serious filtration. This would insure dust free air flowing over the workspace. They use those hoods in labs and even in some clean rooms.
I just looked at my 100-400, I'd have to have Canon's Service Manual before I even thought of taking it apart.
I was not trying to take the lens apart to get to the elements, the locking rings on the 100-400 get gritty after a while, and it is because these bearings jump track. I removed two rubber plugs in that locking ring, removed the screws, and as soon as you do that the bearings go. Had I known they were there in a semi-loose state, I doubt I would have prevented the loss, some would have escaped. Having the lens in the correct vertical position would have reduced the loss.
It is easy to take apart lenses like the 50mm and the 28-135, 17-55, etc, they are like lego toys. The 100-400L is on a different level in my opinion. Also, it is not a sealed lens and dust gets around inside there with ease, doing this in a normally still room in the house with no air flow would be fine, you pumping that lens back and forth puts more dust past the insides than just taking it apart.