HI, I asked the question on the Canon forum "Are the none Canon collar safe" and this is one of the replies I received:- You need to familiarize yourself 1st hand with how Canon's collar functions. It tightens/loosens BUT (critically) does NOT open unless you ALSO pull (vs twist) the knob, thus there's an inherently designed safety feature that will minimize/eliminate the chance of your lens inadvertently crashing to the ground.
I had a friend graciously buy me an Ebay version from Delta as a gift. It looks very similar to the Canon BUT had 2 issues: when tightened there was no "play" in the tightness to allow rotating the lens, although I put some slick tape over the grippy foam and could get some play. When loosened, the ring opened up. If you're prepared for that fine...but if not, crash! I was uncomfortable committing my lens to the quality of the Ebay collar. I eventually found a used Canon one on Craigslist locally and have been VERY happy with it.....should've bought one years earlier!
I don't know that EVERY Ebay knockoff is of similar quality to the Delta product I got (it had a spring that was worthless!) and wasn't about to try each one hoping to find one that was similar to Canon's. Pay attention to the way the ring closes and stays so securely while yet allowing rotation....that's never shown in the Ebay ads!
As I say this is not my review but have to admit because of the possibilities of, as the poster states "The lens crashing to the ground" I waited and found a nearly new used genuine Canon one on Ebay for just under the £50 mark.
My view is or should I say my question is "Are you prepaired to risk a lens that costs a lot money to a none branded piece of equipment"?
When you buy Canon you no you have quaility (I Hope

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