I was looking at the fabulous 200-400 VRII online the other day, and noticed it weighs over seven pounds. Therefore, I thought, it must virtually always be on a tripod. Why would VR be necessary then? Which is to say, one hears that VR should not be used on a tripod (and I assume that carries over to monopod) because they interact badly and cause image problems (see how precisely I understand the issues?). I'd love to hear from you experts what the VR is for and what it is not for on a lens that size. I'm planning on writing a bestseller so I can buy one.