[Oakland Rob]

I just got an old Vivitar 400mm F/5.6 (various iterations; see the database on the forum). It's a sharp lens, on occasion. It overwhelmed the first tripod I used it on; the aluminum lens cap probably weighs more than some of my cameras and doubles as a hubcap...on a 4x4. Someone in the reviews recommended sandbags, and I can see why. I suspect that's an issue with several of these. Kinda neat to have such a sturdy piece, but you find yourself limited to stalking/blinds type outdoor stuff where you can effectively stabilize the thing, like setting up a portable Keck....