There are two schools of thought when it comes to lever clamps, and if you look in the photography forums this topic is almost as hotly debated as whether or not you should put filters on your lenses for protection. The big advantage of a lever style clamp is speed - it is much easier and faster to clamp your camera or lens with a short lever movement, than it is with potentially multiple rotations of a knob. Most knob-style clamps require a full turn to go from fully clamped, to wide enough to lift the plate out of the top, or a quarter turn to loosen the clamp enough to slide your plate out. Many people rely on and swear by their lever clamps.
On the other side there are multiple arguments against them, including:
- Lever clamps have a more limited range of movement in their operation, so they are more sensitive to slight variations in manufacturing tolerances. This is especially true when using rails and plates from different manufacturers. One of the most poular lever clamp manufacturers, Really Right Stuff, recommends using only their plates and Wimberley's plates with their lever clamps. Wimberley recommends not using their popular Sidekick with a lever style clamp without fitting a special adapter, because of potential fit problems caused by variances in the thickness of the powder-coating they use.
- If a lever clamp snags on your clothing, or a tree branch while the tripod is hung over your shoulder while hiking, there is a very small chance it could catch and release the clamp, sending your expensive camera and lens crashing to the ground.
- The clamp opens using springs or spring washers, and over time their performance will degrade.
How valid these concerns really are is up for debate, as you can see on a number of forums. However some clamps like the Photo Clam Lever Clamp (pictured above) address at least numbers (1) and (2) above as follows:
To address (1) above, differences in widths of plates and rails between manufacturers, Photo Clam has a thumb wheel attached to the base of the lever that allows you to adjust the width of the clamp - this thumb wheel provides a good 3mm or more of movement, which should be significantly more than needed for any manufacturer. The Markins lever clamp has a similar width adjustment feature. We tried over a dozen different plates and rails from different manufacturers including Acratech, Custom Brackets, Foba, Hejnar PHOTO, Kirk and Photo Clam. Of the ones we tried (remember these are built to tolerances, so this is by no means a representative sample), the Foba was the narrowest. With the Photo Clam set up for the Foba, several plates (including the Photo Clam and Acratech) would physically fit in the clamp but were too tight to clamp. At this width, others like the Custom Brackets, Kirk and Hejnar PHOTO were too wide to even drop in from above fully open. By the time the clamp was wide enough for the Acratech, the Foba would slip with minimal force while fully clamped, the Hejnar PHOTO would drop in but not clamp, and the Custom Brackets still wouldn't even drop in.
Adjusting the width of the clamp is fairly easy, but slow. Its location and size make it very difficult to operate with your thumb (impossible with gloves on), but relatively easy with the tool provided, or even using a pen. If you use plates and rails from just one manufacturer (this will apply to most people), you should set the width of the clamp once and it will work perfectly for you. However if you use Arca gear from multiple manufacturers, you may have to adjust the clamp every time you switch lenses/cameras, and that more than negates the advantage of a lever clamp.
To address (2) above, the lever catching on something and coming open releasing your gear, Photo Clam has a two pronged approach: First and foremost, the lever will only open half way without pulling back the safety button on the lever. At the half way position, a plate will slide out, but it is not open far enough to allow the plate to be lifted out of the top of the clamp. This is where the detent pin comes in: assuming the plate used has pockets (or grooves of some kind - all of ours do), then the detent pin will catch and prevent the plate from sliding all the way out until you physically push the button to lower the detent pin. Between these two features, simply catching the lever on something could cause the plate to come loose, but the detent pin should prevent your gear from crashing to the ground. Requiring the safety button to be pulled back to fully open the clamp only marginally slows down the operation of the clamp: instead of flicking the lever open with one finger, you now have to grip it with a thumb (to slide the button) and finger to fully open it in one fluid movement. This is still faster than rotating a knob.
Some other manufacturers also use this two-step feature to open the clamp, while some others don't, so pay attention when making purchasing your lever clamp. Without such safety features, the clamps may be faster and easier to use, but the risk of dropping your gear is higher.
As for (3), we've yet to hear of problems being caused by spring washers actually degrading or failing on a lever clamp, but then lever clamps haven't been around for that long yet either. The real question is, will performance start to noticeably degrade in 2 years? 20 years? Or will it never be an issue?
If you have plates and rails (or will have in the future) from multiple manufacturers, you probably want to give lever clamps a miss. From a more purist perspective, if a particular clamp style ties you into a manufacturers (or limited number of manufacturers) gear, then you could argue that's not exactly in the spirit of the Arca "standard". Otherwise whether or not a lever style quick release clamp is right for you largely comes down to a personal preference.