I've just replaced the conventional 200PL-14 RC2 plates on my 20D's grip and my 70-200's collar with 200PLARCH-14 anti-twist plates
. I regard these plates as a huge improvement - I've yet to use them 'in anger', but they should do a much better job of not twisting around when in use.
My setup is relatively heavy - 20D with BG-E2 grip, and either EF 24-70mm f/2.8L (with the camera mounting on the tripod via the grip) or EF 70-200mm f/2.8L IS (with the camera mounting on the tripod via the lens collar). In either setup, but especially with the 24-70, I was finding that in some orientations, the camera was twisting round on a standard plate under its own weight.
For the 70-200 collar, I had to follow the instructions to turn the sliding plate around. It's not that difficult, but don't drop either the circlip or the washer that's under the screw!
A Manfrotto 341 RC2 elbow bracket
was delivered today, which I've fixed to the camera and put on the tripod, but haven't yet used for any shots. It's a much better solution to shooting portrait on a tripod, as you're not tilting the head right over. Leaving it on the camera all the time is really a bit cumbersome, but it fits in the top of my tripod bag in a padded plastic bag. The only hassle with the bracket is that the camera screw isn't captive; if, like me, you're only going to put it on the camera occasionally, you need to pay attention to the plastic nut that keeps the screw in the bracket when it's not in use. Nevertheless, it's a much cheaper alternative to the likes of Really Right Stuff L brackets - which, whilst lovely, are an expense I can't justify.
There's a helpful picture of the Manfrotto bracket here
. For a Canon camera, you can remove the camera screw with the big grey nut seen hanging down near the bottom of this picture - you need that for some cameras with very offset tripod sockets. If you put the little brass arm you see near the top towards the flat side, and fit the camera facing towards the left of the frame, it works well.
The bracket is in portrait orientation in this picture. Note the plastic 'keeper' nut on the camera screw - that's the bit you mustn't lose. Frustratingly, the big hole behind the camera screw isn't deep enough to push the keeper nut into to keep it safe. I shall simply train myself to put the plastic nut on the QR plate that I remove from the camera. With this flaw acknowledged, it's still a good product, though I wonder whether it would have been better designed to accept an RC2 plate on the camera rather than fixing directly to the camera.
Of course, neither of these products are essential, but they're worth thinking about for the future. You can do a great deal with RC2 stuff without having to step up to the expensive Arca Swiss products.
David