Sliding matte boxes

[QuickHitRecord]

I came across a new mattebox from a company called Lock Circle that offers an impressive solution to address the main problem associated with using still photography lenses for video production:

[media]http://vimeo.com/41414067[/media]

(Skip to the 3:50 mark for the matte box demo).

I already own a mattebox and looking at this clever sliding design, I am trying to think of a way to accomplish the sliding motion by modifying one of the many 15mm rail blocks like this that are available on eBay:

[img]http://i.ebayimg.com/t/M6-Thread-Rail-Block-Rod-Clamp-fr-15mm-Rod-DSLR-Rig-Rail-System-Follow-Focus-/00/s/MTAwMFgxMDAw/$(KGrHqN,!nUE-wmo(CICBQBYwE0efQ~~60_35.JPG[/img]

This would be a universal solution that could be adapted to any existing matte box (as far as I know, there is no rail block on the market with rod holes lined with ball bearings).

With no modifications other than to loosen the thumbscrews that tightens the metal around the rods, there is already a promising range of movement. But it still needs a reduction in friction to be truly useful.

My first thought is to pour some lubricant on the rods. This would allow your matte box to move around easily. Unfortunately, it would also cause everything else on your rods to slide around like an ice rink full of kindergarteners.

Second thought: buy some of that padding that people put on the feet of their chairs and couches to keep them from scratching the floor, cut it into short, thin strips, and then line the rod holes. This could possibly work, but it also might not leave enough room for the block to slide freely around the rod. Also, I could see it easily becoming unstuck after just a little friction.

Then there is something like this, which could be left disengaged for maximum rod mobility:

[img]http://i.ebayimg.com/t/Fotga-Quick-Release-Slide-Slot-Block-Clamp-for-Ffollow-Ffocus-15mm-Rail-Rod-Rig-/00/s/NDAwWDQwMA==/$(KGrHqV,!q0E+og)2RDkBQJNNUtGEg~~60_12.JPG[/img]

But there is no front-facing screw hole to accomodate a standard-type matte box riser.

I'll continue to think about this, and if I have any findings, I will share them here. In the meantime, please feel free to share your own ideas and solutions as well.

[Axel]

Teflon covering on the sliding block as on the Igus sliders?

[andy lee]

You can add bump stops that screw into the ends of your rails to stop the matte box assembly falling off your rails by accident.
I've been using this sliding matte box principle now for a few years now
I use an Arri matte box and it slides nicely on my Tecnoir Cinema Rig

.........Also I like using Fujinon B4 TV ENG lenses as they dont extend at all when you zoom or focus
so your mattebox doesn't need to move back and forwards!

[Tim]

You could buy just the slider support mount from Lock Circle for $160.
[url="http://www.lockcircle.com/matbox/buy/"]http://www.lockcircle.com/matbox/buy/[/url]

Might save yourself some hassle trying to do it yourself (I couldn't think of a good way to make one work).

[QuickHitRecord]

[quote name='Tim' timestamp='1348898089' post='19163']
You could buy just the slider support mount from Lock Circle for $160.
[url="http://www.lockcircle.com/matbox/buy/"]http://www.lockcircle.com/matbox/buy/[/url]

Might save yourself some hassle trying to do it yourself (I couldn't think of a good way to make one work).
[/quote]

I didn't see that when I was on their site. Perfect.