Originally Posted by Jon
Off the top of my head, and not owning that particular head, I'd say that the "tension control" is achieved by how hard you tighten down the main ball knob. I've only seen a separate tension control (achieved by essentially a coaxial knob either within the main knob or at the other end of the main knob's shaft) on the pricier heads. If there is a separate BH-11 (and it's not just some store's carelessness in identifying the model number; there's not one listed on the Tiffen site, and they should know) I'd expect it to be one without the Quick release.
For the sake of concreteness, I have attached a picture of the BH11. It appears to have a quick-release. So there goes that hypothesis.
One difference between the picture of the BHQ11 in the original post, and the attached picture of the BH11 is that the BHQ11 seems to have a "coaxial knob."
I assumed that the coaxial knob was pan lock, but perhaps it's tension control? In that case, is there a separate pan lock knob not pictured?
Incidentally, many of the made-in-China ball heads on eBay have the separate tension control knobs. So it's not something only found on pricier heads.
Has no one ever seen or used a Davis and Sanford head?
Let me reiterate my request for more and better pictures and a downloadable manual for these products. Also, it would be nice if someone at Tiffen were monitoring this thread, and could weigh in.