Can anyone tell me how useful they find the tripods with pivoting center columns? I occasionally do some full spherical panos and something like that looks like it would be particularly useful for shooting nadir shots, especially in confined areas. I've never had the opportunity to test one of these out in person, however, so I can't say if the concept is workable or gimicky. Is a horizontal column even all that stable? Do you have to counterweight it to keep the whole thing from falling over? Are the center columns long enough to get out past the support legs and make a usable nadir shot? Some insight from the people who use them would be most welcome!
I'm currently looking at several tripods, including the Manfrotto 055CXPRO4 and Induro CX 214 that have pivoting center columns and the Feisol 3442 or 3441 without. In any case I need something light that packs small and will support 7 - 8 kg. I intend to put on it an R-D16, NN3.1, 40D and Tokina 10-17. (It will also get the much heavier Canon 17-55 f/2.8, but that doesn't get used for nadir shots often if at all).
Also, when you start getting into 200mm and longer do you find the need to have a leveling base increase? I am wanting to attach the NN3 directly to the legs but wonder if an EZ-Leveler or Q3 would be necessary for those long focal lengths.
I use a Benro Tripod A-298 n6, aluminum flexipod which has a pivoting centre column. It comes in a carbon fibre version as well. I think it is useful for doing the nadir shot in low light conditions. I usually don't need a counter weight and setting up the centre column at an angle over the nadir usually feels a bit risky, but it works. My gear is similar to yours in size. I use a Pentax K20D with the Pentax 10-17 mm which is actually the same lens as the Tokina. I did look at the Manfrotto 055 but preferred the Benro because the column could be adjusted to an angle and not just 90 degrees.
I use the Manfrotto 055MF3. Pivoting the center column is not as quick/simple as the newer design. Need to disassemble the column, remove, pivot, then reassemble.
I use the horizontal column mostly for closeup/macro work to reach out over the subject. It is fairly stable with the legs fully spread. But even a lightweight Canon Rebel body with a 24-70mm will limit the stability, especially when the column is extended out beyond about 75%. There is lots of leverage on the extended arm which can move when windy. It is a nice feature that works well, but don't leave it unattended. Especially with your gear extended out over a bucket of water lilies!
My local favorite camera store had a Manfrotto 458B in stock. It's part of the Neotec line. The legs were fabulous. Just pull them out and they stick in place with no twisting or latch flipping. Just pull and they stay pulled until you push a release button. Very fun. It does have a horizontal center column, but in its case the column must be twisted into two pieces and reassembled in the horizontal position. Not too difficult, but also not the most convenient. With the column fully extended horizontally I put about 2.5 lbs of gear on the end. The tripod was totally stable without the slightest tendency to tip towards the weighted end. Very nice! Unfortunately there was quite a bit of bounce to the column, so it was necessary to let the camera sit for a bit with the mirror up to let all the vibrations work themselves out.
One thing that makes me wonder about the arrangement is that in a horizontal setup the camera ends up several inches lower than with a vertical column. Your head, rotator, and anything else that would normally lift the camera are instead pointed sideways. So to shoot a nadir from the same height as the rest of the image you would need to extend the legs, and that would necessarily be a bit of a hassle. I think the variable-angle columns would do better in this by far. I'm hoping my local Calumet has an Induro CX-214 I can play with.
I may end up ignoring all this horizontal talk and going for one of the Feisols. They are smaller and lighter than anything else, and from reports don't sacrifice stability to get it. And for me, the best tripod is the one I take with. 18" folded is a big, big deal or me. 21.5" is pushing too big. I wonder if the Induro can be disassembled to pack less than that? Still waiting to hear back from the distributor if the RD-3 or RD-16 are too big for the relatively tiny Feisol 3441.