I never use any lens support on my 70-200. Yes, the lens is heavy, but in the past I used heavier lens on other cameras and the mount took the stress. The mount on the C300 (I have not tried the C100 ) appears to be robust. The truth is I always seem to be in a rush when I changing lens - not wanting to miss the scene - so I don't really have time time for lens support. If I'm shooting handheld, which, remarkably seems to happen more and more, because of the fantastic IS, I find myself supporting/cupping the lens with my left hand while I focus and zoom. I tend to change lens a lot if I'm shooting a really interesting scene. I guess, for more varied angles, so I have gotten into the Zen of figuring out smooth, fast changes.