Leg locks are the securing mechanisms fitted to the extendable leg sections of tripods and monopods that clamp and hold each leg section firmly in position once it has been extended to the desired length, preventing it from sliding or collapsing under the weight of the camera and lens mounted above. They are among the most frequently operated components on any tripod or monopod, engaged and released repeatedly during every shooting session as the photographer sets up, adjusts, and packs away their support equipment, making their design, quality, and ease of operation critically important to the overall usability and reliability of the tripod system.
Leg locks are available in two principal designs, each with its own characteristics in terms of speed of operation, security, and durability. Twist locks, also known as rotary locks, work by rotating a collar on the leg section to tighten or loosen a clamping mechanism around the inner leg tube, securing or releasing it with a twisting action. Twist locks tend to produce a slim, snag free profile on the tripod leg as there are no protruding levers or clips, making them less vulnerable to accidental release when moving through vegetation or confined spaces, and they are generally considered to provide a very secure and even clamping action when properly tightened. However, they can be slightly slower to operate than clip locks, particularly when wearing gloves, and may require more deliberate attention to ensure they are fully tightened.
Quick release clip locks, also known as lever locks or flip locks, use a hinged lever or clip mechanism on the outside of the leg that can be flipped open to release the leg section and snapped shut to clamp it firmly in position in a single rapid action. Their speed and simplicity of operation make them the most popular type of leg lock among photographers who need to set up and adjust their tripod quickly in the field, as each section can be extended and locked with a single one handed motion. The external position of the lever mechanism does however make clip locks somewhat more exposed and potentially vulnerable to accidental impact or damage, and plastic clip components can be susceptible to breakage if subjected to rough handling or used in cold conditions where plastics become more brittle.
Tripods with multiple leg sections - typically two, three, or four sections per leg - have a separate leg lock on each section, requiring all locks on a given leg to be released before the leg can be extended and re-secured at the desired height. The quality and consistency of the leg locks across all sections is an important factor in the overall stability and reliability of the tripod, as a single poorly fitting or worn lock can compromise the rigidity of the entire leg. Metal leg locks are generally regarded as superior to plastic equivalents in terms of durability and long term reliability, offering greater resistance to impact damage, wear, and temperature related brittleness, and representing a worthwhile investment for photographers who use their tripod regularly and in demanding conditions.