Matte Box Rod Support Snagging on Arri Dovetail Plate . . . is this normal?

[Elizabeth Lowrey]

I have a Petroff matte box I bought several years ago with an eye toward one day owning a RED camera. I never used it, just left it in the box until the last couple of weeks, when I've been completing the rigging for my new Epic. The Petroff works as either a clip on or with (in this case) 19mm rods via a bridge support bracket (which I prefer when using my longer lenses because I'm letting the mattebox support double as lens support.) I'm using the x 19mm bridgeplate with riser to bring the Epic to industry standard 19mm compatibility.

The hitch is that the support bracket for the matte box snags on the front of my Arri dovetail plate if I try to dismount the camera from the back end of the plate, and, conversely, it won't even allow me to mount the camera from the back end of the plate because the bracket is clearly protruding below the bottom of the bridgeplate itself. I tried reversing the bracket (turning it upside down), but it snags in either configuration. Since I'm using a safety dovetail with hard stops on the front and a spring loaded saftey catch on the back, it's necessary to mount the camera from the rear of the plate. I've considered but rejected (for reasons I won't go into) the feasibility of reversing the dovetail plate on the tripod so as to put the spring loaded safety catch on the front side and the hard stops on the rear. While this would allow me to mount the camera in reverse, backing it in from the front of the plate and thus bypassing the possibility of the matte box support bracket coming in contact with the dovetail plate, it causes other problems with my configuration that I don't want to have to deal with.

My question is whether this is a normal limitation of matte boxes used in 19mm studio configurations, whether the Petroff bracket is just poorly designed in not allowing the proper clearance, or perhaps whether the WC baseplate is at fault for not including a thick enough base below the level of the rods holes so that the rods themselves sit up a bit higher vis-a-vis the level of the dovetail. For the life of me, I don't know how the support bracket could be much shorter profile than it already is, so I'm inclined to think the problem is more due to an inadequate amount of thickness on the WC baseplate below the level of the rods holes.

I went with 19mm rods instead of 15 because I like the idea of being able to use one length of rod and slide it back through the baseplate to fit a number of different length lenses, something you can't do with 15mm rods because they run into the camera front. But I'm thinking now I will either have to deal with the inconvenience of removing rods everytime I want to move the camera from the dovetail plate or else go with the 15mm rods that sit up higher and won't therefore interfere with sliding the camera fore and aft on the dovetail. Or maybe go with a different baseplate with a thicker bottom.

Thoughts anyone?

[ericyoung]

This is usually more a matter of mixing accessories from different manufacturers. While there are certain industry standards such as lens centre to rod spacing, other dimensions are not defined and so are open to interpretation by manufacturers.

Personally I'd prefer if everyone adhered to making film style stuff compatible with Arri accessories, but not every manufacturer sees it that way, or may even deliberately use their own standard to lock users into their own full accessory system. Or some like Chrosziel have been leaders in a different field (broadcast) and moved into film style accessories.

If Petroff made a baseplate I'm sure they would design it so their mattebox support would clear it.

[Elizabeth Lowrey]

Thanks for the reply, Eric. Since I wrote this post, I reversed a middle piece on the bracket without reversing the bracket itself, and that got it up just high enough (and I mean by like a millimeter or two) to clear the plate itself. But the bracket still snags on the stop screws, so I'm not home free. But at least this way I can undo the screws (I'll probably use just a single one as a safety stop) every time I mount/dismount, and that will alleviate the problem. It will do until I come up with something better.

[Conrad Hunziker]

Put the arri plate "backwards" on the tripod, so you slide the camera in from the front. I do that anyways regardless of clearance issues, as I think its easier to handle.

[Elizabeth Lowrey]

Put the arri plate "backwards" on the tripod, so you slide the camera in from the front. I do that anyways regardless of clearance issues, as I think its easier to handle.

Hi Conrad, I think you missed this from my original post:

I've considered but rejected (for reasons I won't go into) the feasibility of reversing the dovetail plate on the tripod so as to put the spring loaded safety catch on the front side and the hard stops on the rear. While this would allow me to mount the camera in reverse, backing it in from the front of the plate and thus bypassing the possibility of the matte box support bracket coming in contact with the dovetail plate, it causes other problems with my configuration that I don't want to have to deal with.

I have the shoulder portion of the WC shoulder rig on the back side of the plate and a WC Nato rail mounted to the underside of the front of the plate to allow for quick release NATO clamp mating of handle bars to the plate. Reversing the plate would cause all kinds of issues with that configuration which would take far to long to explain. But I don't want to mess up that configuration.

In addition, I guess convenience is a very individual thing, as when I was trying to mount the camera from the front, I had a much tougher time.