100-400 problem?

I was shooting the other day with my 100-400 lens and noticed what appeared to be parts of a gasket falling out of were the two tubes? Overlap. Now the push-pull zoom does not feel quite as smooth. Has anyone else had this problem and is it in need of immediate repair? It doesn't seem to effect the image quality but I don't want to do any damage if I keep using it.

Norrie

What may have failed is the "clutch" mechanism that adjusts the zoom tension when you turn the ring.

I would think that there would be some type of gasket or seal between the two telescoping tubes. It sounds as if it has become dislodged and probably should go to Canon for a check-up.

If you are referring to bits of "black" flaky material being left on the inner tube as you slide it back and forth...and you are noticing that you have to tighten the compression locking ring more and more... it is indeed the "clutch assembly" and it is a Canon depot level repair. It will cost you some bucks. Had mine done a few months ago at the Irvine facility.

If this matches your symptoms...no it doesn't effect the IQ.

You should not nor have to "crank" down on the locking ring to stop the tube from sliding.