The Wikipedia tripod page mentions that most tripods are braced around a center post.
However, in in this slightly amusing cheapo tripod test video, I noticed the Gitzo tripod isn't braced around a center post whereas every single one of the cheapo tripods is braced around a center post. Thus, based on the very low sample size:
- Cheap tripod = braced around center post
- Expensive tripod = not braced around center post
I recently bought a cheapo ($50) tripod that is not braced around a fixed center post. When looking at the video, the amount of wobble in my tripod is much, much closer to the amount of wobble in Gitzo than to the amount of wobble in the extremely cheap tripods in the video. I don't have a Gitzo so I can't do a fully scientific comparison, but the wobble in my tripod seems extremely low, and after purchasing it, I was positively surprised by the very low wobble, because I knew the tripod was cheap and lightweight.
When thinking about the bracing around the center post, it may not be entirely free. My tripod even doesn't have a fixed center post! To have the fixed center post, you would need more material, thereby having more weight. The same weight could be used to make the legs more sturdy and the joints higher-quality.
So: is there any benefit in having a tripod braced around a center post? What is the purpose that some tripods are braced around a center post? Is it low wobble, or higher weight rating (my tripod has only 2 kg rating, with 1.5 kg ideal load, with the tripod itself being 0.9 kg and the weight I'm planning to use at most 1.0 kg)?
I can at least name one benefit of NOT having a tripod braced around a fixed center post: the "stick" that holds the camera can in some tripods be turned downwards, so that you can have the camera very close to ground level. My tripod doesn't have this feature, but the Gitzo does.
Certainly, given the evidence in the video, adding a center post to a poor tripod doesn't automatically make it a good tripod.