When I was shopping for a ballhead, I asked Kerry at Really Big Cameras this question and he said the 36NS should be fine for 70-200 lenses. He did, however, suggest that I go with the Pro Gold II ball head, which has a slightly larger ball diameter of 38mm and better construction, if I intended to use longer lenses with my tripod set-up. The reason he gave was to reduce possible vibrations, which become magnified at longer focal lengths. I went with his suggestion and have been happy with the Pro Gold II ballhead on my Feisol 3441S. I have used this combination with my 100-400 lens and the ball head had no problems locking and there was no creep. It is also small enough to fit between the tripod legs when folded.