A "ball head" is what landscape photographers use to connect their cameras to tripods. It's the business end of a tripod, and good tripods are crucial to landscape work. Ball heads must be smooth, reliable and strong. You don't want your heavy camera flopping down, you want it to remain pointed exactly where you aim it, even when you have a very long, heavy lens attached to it. Consumer-grade ball heads are prone to failure. Even when they work, tend to creep a little bit after you let go, changing your composition. Right now I can't think of anything more annoying.
Serious ball heads for serious photography tend to cost serious money... typically from $400 to $1,000. They are precisely machined by hand from expensive materials and manufactured in small quantities compared to consumer products. But recently as I was looking for a new head, an alternative came to my attention: the Sirui K-40x. This head is significantly less expensive than its competitors, yet seems to have all the quality, strength, fit, and finish it needs to do the job and be unobtrusive.
Like most professional ball heads, it comes in a soft case that doubles as a protective cover when mounted.
This head has only two control knobs: a friction clutch and a panning lock. The friction clutch employs an integrated governor that allows you to set the minimum friction so that even when loosened all the way, the head won't allow the camera to flop around, but will allow it to be precisely positioned.
The one-knob solution to setting the friction works perfectly, and removes the annoyance of trying to figure out in the dark which knob to reach for. It is a major improvement over two-knob heads and I will never buy another ball head without this feature. Set correctly and unlocked, you can smoothly position the camera without any play, yet have enough firmness to keep the camera from falling over. The friction is firm but smoothly yielding and the composition can be framed precisely. Plus, you can't accidentally remove all friction from the head; it will stay at the safe minimum. When you lock it down, it responds with remarkable solidity and doesn't creep from where you placed it. (Cheap heads change position minutely as you tighten them.) The smaller panning lock works as expected and because of its size and location, it can't be confused with the friction clutch in the dark..
Like other professional ball heads, this one is large (the ball has a 54mm diameter) and relatively light. It's made from a block of machined aluminum. Small ball heads are fine for casual use and wide angles, but longer, heavier lenses with more magnification require bigger, stronger ball heads like this to steady the camera completely and prevent blurry pictures.
At the top of the ball head where it meets the camera is a clamp designed to hold the Arca-Swiss style quick release plate which is screwed to the bottom of the camera. This is a simple screw mechanism, reliable and convenient. On my camera, rather than a quick release plate, I have added an L bracket. It also fits in the clamp on the ball head, but allows me to mount the camera in either landscape or portrait mode. It also prevents unwanted rotation of the clamp where it meets the camera, which can happen with heavier lenses... the plate begins to unscrew itself from the camera when there is torsion.
L brackets should be custom fit for your exact camera model... never buy a generic L bracket as it will only cause annoyance and you won't use it.
This then is the Sirui K-40X professional ball head. Only time will determine if it can last for years like other professional ball heads. Sirui thinks it can, which is why the head comes with an astonishing 6 year warranty. So far, I'm very pleased with this crucial piece of gear, not even accounting for the reasonable price.