Smallest arca clamp?

What is the smallest arca Swiss compatible screw clamp that also has the safety stop release?

There are two styles of safety stop in use of which I am aware. One style has a pin on the clamp itself (see Acratech for an example), the other has screws on the plates, with channels on the clamp (see Really Right Stuff and Kirk).

I am not certain of the smallest, but I've seen 1" wide jaws, with channels to make use of the plates that have screws on them. Check out Hejnar, and Sunwayfoto.

Then there is the matter of making sure it fits on the head.

I'm familiar with the pin in the clamp, you have to unscrew the knob then press the pin down to slide the plate out.

How do you release the plate if there are screws in it? Does it not slide out.

Just unscrew the knob a bit further and tilt it to release.
I have Arca type clamps and plates designed for both types - I prefer this system as I find it more positive.

This is the smallest one I have;

http://www.amazon.com …s=neewer+arca+s​wiss+clamp

I wish I would have done more research before I bought into this system, I bought a sirui k30x ball head and a few QR plates but the plates have screw stops which aren't compatible with the sirui mp-20 clamp on the ballot it uses a pin on the ballhead for a safety stop.

I have the K40X and no problems with the plates with screw type stops so long as they are a bit longer than the clamp. Some plates are hollow underneath (like Sirui) most will engage the safety stop on the clamp. Others are solid so they just depress the clamp safety stop and rely on the screw type safety stops on the plate - this is why they need to be longer than the clamp. Get plates of 70mm or longer if you are using the screw type stops or ones that are hollow underneath so that they engage the safety stop on the clamp - then you can just remove the screw stops.
I hope that makes sense!

Yes it does, but only because I experienced it first hand now, I bought a plate that fits my 5d3 but it had screw stops, I had to remove the acres for it to fit, I'm sure it would have worked fine, but I want the added safety of the retaining pin.

Cyber I looked at that clamp and almost got one to mount on my strap, but I decided to get a sirui clamp that had the retaining pin, it's the same clamp that comes on the sirui ball heads.

Didn't your K30X come with a QR plate? My K40X did - that is the plate I use on my camera. My longer plates (of various types) are mounted on lens feet where longer plates are an advantage and the screw stops don't interfere.
If you live in the UK I have a spare Sirui plate if you want it. It's a little wide but it works just fine.
Alternatively these cheap plates work perfectly with the Sirui clamp though you will have to adjust it if it is a Lever Lock type. If it is the screw type then they just work, I have a few of them, you can take out the screws if you like as the Safety stud on the clamp engages the plate properly.

http://www.ebay.co.uk …82600?hash=item​58b6c05f08

regarding the safety stop screws, I'm tepid on them. Some of my plates I've removed them, some I left on, they are a toss up between safety and speed/convenience, which for over a decade now and I still have not come down on one side or the other firmly enough that my plates are either with or without.. stil a mix.

Oh well.

That said, that's my lack of position on them, if one is invested in them and lie the safety feature, i think they do the job well.

On the safety note... I had a Kirk BH-1 for 11 years. It is was an older design and the clamp didn't have any safety features. Once I saw how tightly it held the plates, I had no worries. And no accidents in that time.

I later changed to a lighter ballhead (Arca-Swiss Z1) with a RRS LRII clamp (because I finally got an L-bracket, and the older screw knob was quite slow). The new clamp has safety channels, but I still don't have any plates with screws. The LRII holds the plates so tightly that again I have no fear. The end of the lever wraps under the camera or lens and is very unlikely to catch on anything.

Thnx john, but I live in the states, my k30 did come with a plate, but I use a strap actually a double strap and there are times I will run ahead and the force of a 5d3 with a 70-200 2.8 IS ii could create enough rotational force to loosen the screw that holds the qr plate, so I bought a 5d3 specific plate that conforms to the bottom and sides of the camera.