Tripod Leveling Bases: Panning on the Level
A photographer goes out to take some photos on a beautiful summer morning. He sets up the tripod to the desired height and takes a shot. He then pans the camera over to one side and finds that it's no longer level. He takes a few shots after readjusting the camera to level it again, then swings it back to the other side, and finds that the camera is crooked again.
I know I've experienced it. The problem is, even though the camera may be level, the platform on the tripod itself isn't so when you pan side to side the camera ends up all cockeyed. Trying to level the tripod by adjusting the legs can be a frustrating experience, but there is another solution to this whole problem. Both Gitzo and Bogen/Manfrotto make tripod levelers that insert between the legs and head and enable you to square your view of things with reality, even when you pan the camera.
The Gitzo G1321 Level Base weighs about a pound and a half and only works with certain Gitzo legs. Replacing any existing center column, it has a handle that hangs down between the legs. Loosening the handle permits you to quickly level the head by means of an integrated ball joint at the top. The Bogen 3502 Ball Camera Leveler (Manfrotto 438) weighs about the same but will work with any tripod. It fits between the tripod legs and head by means of the existing standard 3/8" screw connection found on each. It has a locking lever on the side that allows you to adjust an internal ball joint similar to that on the Gitzo.
I started out using the Gitzo but have since switched to the Bogen as I found the 4" long handle on the Gitzo prevented me from spreading the legs all the way and getting the tripod to ground level. If you plan to do a lot of panoramas though, you'll be glad to have the Gitzo handle as it is somewhat easier to adjust than the Bogen. Both levelers work quite well and each includes an integral bubble level so you can tell when you've got things level.
I don't always bother leveling the tripod, but when I do need to, it's nice to know I can without spending 15 minutes fiddling with the length of each leg.