When I first saw it at the local shop, I realized that it is very solid. The braces have a cross-section of 40.5x8.5mm, though I don't have any idea of which metal. Probably duralumin or something similar. It does not feel heavy enough for iron, but it is not yielding like plain aluminium. It is very professionally made and the build quality is high, akin to the best L lenses.
In any case, I tested it with my 400f2.8L II. It was easy to attach the lens to the long quick plate that was supplied with the support. The only problem is that the center of gravity of the lens is slightly higher than the highest pivot point on the support.
If I put the support below the lens, then it is very unstable - even the slightest movement will soon tip the lens over as the imbalance increases all the time. However, when the lens is hanging from the support, the position is very stable. Any movement will return the lens automatically back to vertical.
I took a few images without even locking the lens, and they were good - although for best results I would recommend locking it. It was fast to move the lens around, and the 400f2.8L II became almost weightless. When the support was locked, it felt much more solid that any mount head I have been using so far.
The locking mechanism makes it possible to decide how easily the lens can be turned, both horizontally as well as vertically. Small movements are possible and there is no backslash.
I also tested it with my 70-200f2.8L IS and 200f2.8L II. In fact, the topmost pivot holes seem to be quite OK for these lenses as well. Both lenses felt extremely solid, and the images were sharp.
I can recommend this lens support to anyone who has a heavy telephoto lens. It makes even a heavy lens almost weightless. The 400f2.8L II probably would benefit from a lower tripod foot, but it works quite well even with the original one.
I have a hard time thinking how the Wimberley Gimbal head could be any better than Manfrotto 393. At one third the price, it is a bargain!
