I almost never hand-hold my Hasselblad, so the size and weight of the 250mm for such is irrelevant to me. I will on occasion hand-hold the 80mm or 50mm, but it's the odd grab shot. Now that the OP mentions that he's shooting Antarctic icebergs from a ship, the 350mm doesn't seem unreasonable. It's a big, heavy lens, and I've handled but never used one. I've never seen a Hasselblad 500mm, but I'd imagine they're not common. The 350mm shows up on KEH's site once in a while.