Canon EF 100-400mm f/4.5-5.6L IS II USM Lens retracting when pointed almost straight up

[Mitsubishiman]

I searched and did not find a topic on this, any suggestions, my issue is, with my Manfrotto 190 set sideways so I can take a shot almost straight up, the weight of the lense tracked out is sufficient enough to case it to retract under its own weight, I can get the shot but I have to hold on to the lens with one hand, any suggestions, I could do a much better job on the focus if I had both hands free  

[ebiggs1]

A rubber band or some of those squishy things girls wear in their hair.  Pretty easy and pretty common fix.

[Waddizzle]

The lens has a friction ring adjustment.

[ChrisPBacon]

I use painter’s masking tape on this lens while photographing the moon: it doesn’t leave any tape residue on the lens.

[Waddizzle · Accepted solution]

The friction ring should be strong enough to “lock” the zoom in place. If not, get it checked. You could have something being stripped inside the lens, creating who knows what sort of future havoc.

[TCampbell]

As Wadizzle points out ... the 100-400 II has a "tension" ring to prevent zoom creep.  After you zoom, snug that ring.  If the zoom still creeps after snugging the tension, then the lens probably needs an adjustment (send it in to Canon).

[Mitsubishiman]

Thanks for the information, I was not aware of the tension ring, so I feel a bit ignorant, it works as described, it was all the way open thus no tension, works perfect.