Oh, and as for that 500mm f4 lens, unless you're my size, 6'3 and about 275, carrying that heavy monster around in it's not so little suitcase could be a chore! Between it, my camera backpack, which weighs in at about 50-55 pounds with the bodies and lenses that I usually have in it, and another 12 pounds for my tripod, I sort of feel like a pack ox!