Lens Collar Slippage on 70-200mm f/4

Can anyone suggest a remedy or fix for slippage in the lens collar on my

70-200mm f/4 lens? For instance, if I compose an image either vertically or

horizontally and lock the collar as tightly as I can, there is lens rotation in

the collar if manual focus is used. Turning the focus ring causes the lens to

rotate stiffly in the collar and skew my composition. The collar gripped

tightly for the first five years or so, but now there is slippage. I've cleaned

the inner portion of the collar and the respective outer surface of the lens

barrel. In inspecting the collar's component parts, nothing seems to be

noticeably wobbly or broken. Is there something I can do to restore the gripping

power or do I need to visit a repair shop? Thank you

Have you tried wrapping the lens barrel with a layer of scotch tape? You could add one layer at a time until you achieve a snug fit.

I folded a piece of paper and inserted it between the lens and collar. It works reasonable well.

Thanks for the responses. Won't adding a scotch tape or paper filler restrict my ability to move the lens from vertical to horizontal format (or vice versa)when I need to do that for compositional purposes?

The filler is just there to help lock it down since there seems to be a little excess room. You may have to loosen the locknut a little more to rotate to the other perspective.

>>> Have you tried wrapping the lens barrel with a layer of scotch tape? <<<

 

It is better to line the INSIDE of the collar with tape: very thin felt, with an adhesive back. (like what one would stick on the bottom of an ornament so as not to scratch a polished table on which it sits etc)

 

Lining inside the collar, to achieve a smaller diameter, will put the clutch force onto the lens rather than the other way around.

 

The paper stuck in works too: but lining the collar is a `permanent` fix

 

WW

"Lining inside the collar, to achieve a smaller diameter, will put the clutch force onto the lens rather than the other way around."

 

I don't understand what this means. The forces on the lens and the collar are equal but opposite. All you are trying to do is fill a gap cause by a few thousandths of an inch wear on the friction sheets on the collar. I would be wary of attaching to the collar something as thick as adhesive backed felt which might prevent proper clamp up and be difficult to remove afterwards.

>>> I don't understand what this means. <<<

 

Yes.

 

After I posted this I re read it (wrong time to do a re read).

 

It was not technically correct, a little short on description, and perhaps could have been taken (by you especially) as curt: which it was not meant to be. I was rushing to leave the office for an appointment and I wanted to enhance what you wrote.

 

I have done this, (not to a Canon lens but the principle is the same).

 

At three or four points (I used three) at equal distances inside the collar attach a thin (about 1mm uncompacted adhesive felt, Note: really thin. You might have to hunt for thin stuff.

 

I understand the clutch is only at three or four points around the diameter, but it worked for me without any slippage the thumb screws on the Canon collars are a good thread, for a strong bind.

 

The `Clutching force onto the lens` comment was referring to the fact that the FELT is clutching onto the lens, not the sticky bit. (i.e. it was not referring to the moments of the forces pre se.)

 

The reason is: It is really easy to apply alcohol or nail polish remover to the collar and remove the sticky later if that is required; but much more caution is required to remove the goo from the lens.

 

I think the collar will be able to be loosened to allow this application, provide the felt is thin.

 

Trust this better explains my original post and my apologies for being less than clear first up.

 

WW