Originally posted by stl09 I currently have what I felt was a fairly heavy duty tripod to handle larger loads, it's a Vanguard B-200 Tracker tripod and a SBH-200 head.
When trying to use my Sigma 50-500 and even the Sigma 100-300 and the K-7 I have a great deal of difficulty getting the head to stay in place. It keeps moving due to the weight. It's not bad if it's straight on for landscape shots but if its at any type of angle forget it.
It took me a little bit to understand how to use a head with a tensioner as I had never used one before. Bear with me as I explain what I have found works as I think I need to explain it to ask if that is how you are currently setting up the head. I tighten the main knob until the head locks with the lens, then adjust the tensioner to be as tight as the main knob, but backing off the tensioner a little, very little from full tight. On my head this can be as little as 5-10 degrees. At this point I loosen the main knob and see if the tensioner will allow the head to gently move, but hold, when the head is positioned, tilted, toward its side, but not actually on the edge of the head. If not, I tighten the main knob and back off the tensioner and repeat. Once the tensioner side is smooth, I will tighten the main knob enough so that when the lens is positioned toward it, it still moves, but holds when released. This should allow the head to glide to, and then hold, at any position at the top of the head.
Without an elliptical ball, even with the fine adjustment done for the top of the head, moving the lens into the slot will probably not hold with a heavy lens, but since the tensioner is pretty well set, it should only take a little more tension on the main knob to hold the lens in place, very little, when moving the lens into the slot.
So if you are doing this and still the lens won't hold in the slot, then you probably need a new head. If not, practice a little with the head to see if you can get to a really good balance between tensioner and main knob at the top of the head. Then see if the lens will glide and hold in the slot with a little bit more tension. I prefer to have the tension optimized for use at the top of the head and then add the little tension when in the slot, versus having the tension set for the slot. This just makes it easier to work with the setup without having to apply what seems like too much force when the lens is on the top of head. An elliptical ball would probably be the better solution, but at the time bought, elliptical balls were way over my budget.
Thank you
Russell