|Benro GH2 Gimbal head|
|Pentax A* 300f/2.8|
|Accepts Arca-Swiss mounting plates|
|Pentax A* 400/f2.8|
|Pentax A* 400/f2.8|
|Pentax A* 600/f5.6|
|Pentax FA* 300/f2.8|
When you think of a tripod for photography equipment you need to think in two parts. One part is the Legs. the other is the Head. Low end tripods will have these two parts integrated but the better quality and upscale tripods will be separable. It's not only a chance to get money from you twice, but also consistent with the fact that there are several styles of 'heads' for tripods and for different equipment different ones are appropriate.
Most tripod heads whether removable or not, attached to the legs and then simply attach to the bottom of the photographic equipment. Fortunately there are standard screw sizes for both legs to head attachment and and head to camera attachment. Variables include 'quick release' solutions, balancing offsets, and some way to point the camera without turning the legs. With equipment that will do video, a head that will pan smoothly is a necessity.
The gimbal head is really a special head for long heavy lenses. It has a side arm that reaches around and above the lens. The equipment then pivots from this 'side arm'. The result is that if the lens is reasonably balanced it won't take a header if you turn the tightening screw loose to adjust it and hen forget what you are doing. IT will just hang reasonably level much like a child sits in a swing....
This particular head which is from China appears generally to be a knock off of a similar looking head known as the Wimberly head. It's rated to hold 23 Kilos (around 50 lbs. The equipment is mounted, and adjusted for balance using the Swiss-Arca style plates which clamp to the base unit and depending on the length of the plate,can be adjusted fore and aft to find the balance point. The unit comes with a 100mm mounting plate (4 inches) which has around 2 inches of travel. This is sufficient for smaller lighter equipment or equipment that is closely balanced already. It is marginally enough for the Pentax 300mm lenses, and even works for the 400mm f/2.8, but is totally inadequate for the 600mm F5/6 Pentax which is grossly out of balance. Longer lens plates may be ordered at extra cost, and I have ordered a 200mm long one for my 600 mm lens.
These heads seem to be sold in several different sizes. While they generally all have a weight capacity rating sufficient (this model is rated at 23kg (about 50 lbs)) if you have large diameter lens, it may be an issue. There is just marginally enough clearance for the 'fat boy' Pentax 400/f2.8 which is big enough to require a 145mm screw in filter. Benro also advertises a line of other heads and tripods. They even feature an upscale model of this head which has a 'swing lock' for positive locking of the swing arm, and a 'swing brake' which will prevent a violent swing if the swing clamp is released on an out of balance configuration.
Regardless of whether you are using a conventional head or a Gimbal Head, if you have a long lens an adapter plate is likely called for if you have a Quick Release head. I strongly suggest some form of Quick Release as for ever in a day as soon as you get your camera all hunkered down on a tripod something comes up and you want it loose of the tripod. If it is screwed and bolted down within an inch of its life, you will miss the next shot for sure. There are several types of quick releases and you do need to find a way to standardize on one. The Swiss-Arca is a fairly popular one. One of its advantages is that it will take a sliding plate--as long as you need (the come in different lengths) which will allow you to slide your camera forward and backwards to achieve a suitable balance on the tripod. to be sure I've used out of balance lenses on tripods for years, but getting them balanced is a good thing and makes them much easier to use---as well as less likely to take a header and wreck a valuable lens. If you combine a Gimbel type head with a sliding plate with a quick release you have the best of both worlds. When you get your long lens balanced on the tripod you don't even have to set the clamp on the gimbal to make it stay there. You can nudge it around to find your target without having to allow some 'windage' for how much the tripod will bend and bow after you lock it down.