First, a personal opinion
There is more to a tripod than just holding the camera still. While  certainly a primary function, the impact on your photography goes much further than that. When you hand hold your camera you make creative choices based on the speed of the exposure. In an effort to keep the shutter speed fast enough to get a sharp image you let the mechanics of the camera choose your aperture; not the requirements of the scene. It is no different from setting your camera on “Automatic” and pushing the shutter. You are not able to have full creative control because you are allowing the camera to make choices for you. Depth of field can suffer and so do your images. Using a tripod gives you back creative control. You can choose the exposure combination, that the scene requires, with no concern over the mechanics. If the scene calls for f/16 and 2 seconds, you can choose exposure without compromise.

The other benefit is less tangible. Very simply put, it slows you down. It is much easier to do a thorough job of setting up the scene when you have time on your side. You can scan the edges of the frame looking for distractions and decide whether they should be included in your image or perhaps recomposed out. You can take the time to use the DOF preview button on your camera to make sure all of the elements that you want in focus really are in focus.

There are areas of photography where a tripod just isn’t practical; i.e. sports, wedding and birds in flight. For landscape, architectural, nature and macro work I consider my tripod absolutely essential. You can make good images with nearly any camera but if it’s not sharp it’s not a good image. Conversely, a cheap unstable tripod can actually be worse on your images than using no tripod at all.

What to look for in a tripod
There are 3 basic qualities that you can shop for when looking for a tripod. The catch is that you can only pick two:

• Very stable
• Low cost
• Light weight

It works like this: If you want a stable, light weight tripod it’s going to cost more. Low cost and stable is possible; it’ll just be heavy. Get one that’s low cost and light weight and it’s not going to be very stable. If you keep that concept in mind, while shopping, it’ll greatly improve your chance of getting something that will perform well and fit your budget.

Tripod legs generally come in two materials; aluminum and carbon fiber. There are other variations on the carbon fiber models but those are generally the high-end gear; i.e. basalt and magnesium. Carbon fiber is light, very stable but expensive. Aluminum can be very stable but is much heavier.

Picking the right gear
Your height should have a bearing on the model that you select. If at all possible, you want a tripod that puts the camera at your eye level without having to extend the center column. If you already have a tripod here’s a little exercise:

Set up your tripod with the center column down and look through the view finder. Tap one tripod leg and watch the vibration. Now extend the column all the way and repeat. All that bouncing around is bad for your image.

Fewer joints in the tripod legs make for a more stable platform but make for a larger collapsed size. It’s okay to buy a tripod with 4 section legs, just understand that impacts stability somewhat. Since I travel a lot with my gear, I consider that an acceptable trade-off.

Okay – that covers the legs, what goes on top?
The tripod head should be a separate purchase. Always avoid tripods with non-removable heads. There are a ton of different styles of available. Unless you really like the old style pan and tilt heads get a ball style head. You should also pick one that has some sort of quick-release mechanism. Some use a proprietary plate, many of the better ones use a plate based on the Arca-Swiss design. If it’s a hassle to put the camera on and off of the tripod you won’t use it.

Some brands to consider
Tripods: Gitzo, in my opinion, is hands down the best but it’s very expensive. Manfrotto, Slik, Velbon and Feisol all make good quality, stable, tripods. Avoid import knock-off type legs. I’ve heard horror stories about many of them. It’s not a comforting sight to see the head snap off of your tripod and have your camera smack the ground.

Ballheads: I like and use Really Right Stuff but like Gitzo they’re expensive. Kirk, Acratech, Markins and Manfrotto are all viable, reliable options.

My personal setup is a set of Gitzo GT2540 legs and a Really Right Stuff BH-40 LRII head. I also use the Really Right Stuff L-Bracket on the camera and a 79L plate on my 100-400.

One last thing
If you’re going to the trouble of using a tripod you should also invest in a remote trigger. It doesn’t matter if it’s wired or wireless; the key is that you’re not touching the camera during the shot. If you don’t have a remote trigger, consider using the camera’s self-timer feature. If your current tripod is less than stellar, this can make a huge difference in the sharpness of your shots.

Cheers