These larger cameras need to be free of any vibrations, especially when slow shutter speeds are used. Metal tripods are now frequently made of aluminum or other lightweight alloy. There are a few models still made of solid steel, but they are not as popular outside the photo studio due to their weight. Many use square legs that telescope inside each other and lock in place with clamps. Some models, such as the French Gitzo line, use a tubular design that lock in place with threaded collars.
Most users prefer the clamping models as they can be set up quickly.
Users of threaded collar models claim that there are less parts to break and the tripods maintain rigid connections even after years of use. Plastic tripods offer a significant weight reduction while being impervious to salt water, rust, etc. Like their metal counterparts, they are available with square or round legs, but tend to favor clamping connections. Premium priced models are now made of a carbon-fiber material that offers the strength of metal and the lighter weight of plastic. Regardless of material, the object is to always keep the camera rigid and isolated from vibrations.