70-200 f2.8 L IS II Questions?

Hi

I recently bought a 70-200 f2.8 L IS II lens - while expensive, it's a great piece of glass - my copy seems to be very sharp at all focal lengths and apertures. All-in-all, I'm very satisfied except for one issue.

When I turn the zoom ring, it doesn't feel super smooth - there seems to be a slight grinding sensation. It's not bad, but it's real. When I turn the zoom ring on my 70-200 f4 L IS it feels super/silky smooth - absolutely no grinding sensation.

My questions are:

• Is this normal for this lens?

• Should I be worried - is it likely to get worst over time?

• Should I exchange the lens even though the next copy might not be as good optically?

• Should I take the lens to Canon for service (I live less than a hour from the Irvine plant)? Is it likely the sharpness of the lens could be screwed up while in for service?

I love my 70-200 f2.8 L IS II, but I'm worried about this grinding feel/sensation - should I just live with it, exchange the lens, or take the lens in for repair?

Your comments and suggestions will be appreciated.

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Thanks, Ed
Torrance, CA