Thoughts on a few quick-release clamps

I converted to an Arca-Swiss style ballhead and quick-release system over 10 years ago. As most of you know, this style is a dovetail design and relies on friction to hold a plate in a channel.  When I first started reading about them and took a look, I admit I was nervous about the plates sliding out of the sides.  Once I tried one, I was hooked on them and lost my concerns.  Given a properly-sized plate, they clamp down tightly and are completely secure.

Here are my thoughts on the few clamps I have tried.

Kirk (old style) screw-knob:

The first such clamp I ever used was a simple screw-knob type that came with my Kirk BH-1.  It is a very simple but strong design.  It takes a few turns to lock, but as it tightens, you can feel it grip the plate and you know it is secure.   My model is over 10 years old, and came with no safety stops... no pins, no channels as you find in more modern clamps.  But honestly, it doesn't need it.  Such things are for peace of mind only.  I have tried to push out the plates and was unable to budge them.  This clamp is more than strong enough for any application I have.  I love the large knurled design of the knob; very easy to grip even with gloves.

I have only two gripes with this older Kirk clamp (and they are nitpicks):

First is the length of the knob.  If you use the clamp with the knob pointing back at you, it can poke you in the face.  To be fair, this is common to most screw-knob clamps.  It is apparently a deliberate design decision; I have been told they are long to accommodate more plate styles, but I don't use anything that requires it.  To avoid being poked, I think most people use the knob on the other side, sticking out under the lens.  My old film body was short and the lens was always too close to the knob for comfort, so I solved the problem by using a square plate on the camera body and oriented the knob to the left side.  That worked for me for years until a friend convinced me of the benefits of an L-bracket.  Being poked in the face isn't a problem with larger DSLRs!

My second gripe is the speed of the clamp; it takes a few turns to tighten/loosen the clamp.  This wasn't an issue until I finally bought an L-bracket, and I wanted to switch orientations on the bracket more often.  One purchase leads to another, and the L-bracket got me looking at other clamp designs.

Kirk (new style) fast screw-knob:

The image is from Kirk's website.

Since I'd had such good luck with Kirk and thought I'd prefer a screw knob, I tried Kirk's newer fast speed screw knob.  I didn't like it, right from the start.  It didn't take much of a turn to unlock it, and didn't provide quite the same feedback as my slower screw during tightening.  It's faster, but it just didn't feel secure to me.  Also, I noticed that the clamp pushes the plate out of level when tightened, making the level totally useless.  The new Kirk clamp has channels that act as a safety catch when used with plates that have safety screws on the bottom.  And finally, I didn't like the more-rounded knob; it is harder to grip.

Acratech screw knob clamp:

The image is from Acratech's site

A friend of mine has an Acratech GP, which comes with a choice of either a lever clamp or a screw knob.  My friend has the double-speed screw knob. It has a nice knob and a quality feel to it.  I liked it better than the Kirk fast model, but it still doesn't provide the tactile feedback of my older slow screw knob.  My friend's clamp comes with a safety pin that will catch in the bottom of most plates and will help stop a plate from sliding out if it is partially loosened.

Markins lever clamp:

The Markins lever is nicely made with a quality feel.  It came with a Q20i ballhead I rented.  It is the first lever I tried and it was much nicer than I expected.  I appreciate the speed of locking and unlocking. It requires a bit of force and I don't see it opening by mistake too easily, but you could in theory catch the end of the lever on something.   My only frustration is that apparently my older plates have inconsistent widths and one of them wasn't totally tight.  I was able to push the plate out of the clamp with thumb pressure.  The fix is to get plates from one maker that are all the same width, and adjust it properly.   The Markins has a pin like the Acratech model to act as a safety stop with virtually any plates.

I also don't see the point of a level that is hidden under your mounted camera.  To use it, you have to level the clamp before you mount the camera.

Really Right Stuff lever clamp:

This is the clamp I ended up keeping.  Many people rave about RRS gear and now I understand why. I didn't expect to like lever clamps but RRS changed my mind.  I have the B2 LR II, which, as it was made after 2012, has a self-adjusting design that holds each of my varied plates securely.  I cannot push my thinnest plate out of the clamp they way I could with the Markins clamp.  Every plate (all Kirk plates) I own is 100% secure in this clamp.  I'm not saying every plate ever made will work, just that all of my Kirk plates work.

The lever wraps around the edge of the clamp and always ends up under your camera or lens, giving it more protection from an accidental tug (which requires a fair amount of force anyway).   The safety mechanism is the same as the new Kirk clamp; channels which require screws on the plates to stop an accidental slide.   The build quality is excellent; it feels beefy and secure in use.  While I would like an extra lock on the lever for my own peace of mind, I don't think it really needs one.  In actual use, I never give it any thought; I just know it is secure.

It has a scale on both sides of the clamp with marks every 1mm.  However, my L-bracket is fat enough that it covers most of the marks.  I can see the larger marks, just not every 1mm.

General observations:

A brand I would like to try, but have never had a chance, is Hejnar.  I like the short knob versions.

Another clamp design that looks interesting, but does not fit my Z1, is FLM's SRB-60 screw knob clamp.

In screw knob clamps, I found a trade-off between speed and my sense of security.  I'd rather feel secure.

One of the benefits of the lever clamps (this applies to both Markins and RRS, and a few other brands) is that the lever is low-profile, not jutting out above or below the clamp itself.  I can orient the RRS clamp in nearly every direction in my ballhead without hitting anything (it barely touches the base when the lever side is down in the drop notch, but this isn't a problem in practice).  Screw-knobs can hit the sides, base, or other controls on some heads, making some orientations awkward in use.  An L-bracket obviates most of those issues when they occur. 

On a monopod, I prefer a slow screw knob like my old Kirk clamp.  I think it is easier to tighten in that situation.

On a tripod, since I use an L-bracket, I like the speed of the lever.  If I didn't use an L-bracket, I would not care either way. 

What works for you is a matter of preference.