Cinematography Mailing List - CML

Spinning Camera

Going through some shots recently, a director asked for a spinning bottle on the floor. That's as far as his description went so I thought how do I make it interesting? How about looking directly down on it I thought, and the camera spins in sync so that the bottle doesn't appear to move, but the stationary floor does! Ok, a floor isn't a very interesting background, but it would be cool for my show reel and those in the know would appreciate the technicalities of shooting it.

Didn't give it much further thought so far, until a few hours ago I looked over Geoff's BMW spot on (hey, I know that website!). And its concept...spinning a camera around on a spinning subject so that the stationary background is...spinning! Marvellous stuff. Well, I pulled some paper from the printer and sketched some designs just a little less expensive than the rig he used. Quick fill in, his rig rotated camera around the axis of the lens, so that the horizon spins 360, and the subject spins in sync with said axis so that it looks still. Most effective up to a certain rpm, I guess, before the background spins too fast.

1st problem is unless there's a universal rig that can be adapted to both, Geoff's is what I'll call horizontal, ie, rolling sideways pointing out the side, my desire is a vertical one, spinning around, and pointing downwards to the floor. Still with me?

I started with the horizontal (Geoff's) idea. I'm thinking two thick-tread 4ft high tractor wheels, or maybe two narrow bicycle wheels. Can't imagine using an axle as it kind of gets in the way of where the camera is supposed to go, if you understand. So I'll chop that off, and bolt or get someone to weld them together around the inner circumference. Then put in a platform for the camera on a hi-hat to sit without unwanted movement.

Haven't got any ideas for the vertical version, although hanging it on a rope and finding a way to pin its spin dead-on the axis of the lens. Either way, I've got to have the camera exactly straight, and the centre of the lens to match the centre of the rig. And the ride has got to be very circular. Looks like a case of balance, weighting, and measurement – and testing.

Hmmm...writing this I just thought of an interesting way of getting the vertical shot originally wanted. I'll have a 360 track and Egripment Focus dolly (flatbed, designed to stick the tripod on) on the shoot. What if I rented a second dolly for that day. Stuck it on the opposite end of the track, so I've got two dollies on same circular track. Not sure what the diameter of the track is yet, but could lay a strong support between them, with a hole in the middle.

I'll attempt a drawing with my keyboard, something like this from a top view :


(the parentheses are the track, == is the support and the O is the gap in the middle for the camera to look down through.)

Now, the camera is supported in the middle, pointing downwards, putting no weight on the lens of course. And the idea it that as the dollies track around the camera will spin.

Needs enough clearance in the centre to frame up, and need to consider lighting too, as the moving support might cast shadows depending on placement of lights.

There’s also the fact that the bottle needs to spin in sync. Perhaps attach a thin wire on top and bottom of bottle, and go in a straight line off frame, and then up to rotating rig, so that the rig moves the bottle? And do some wire-removal in post.

On the other hand, I've just thought of a second option : have camera upright as normal, on sticks, attach a sample of the flooring (as it will be matching other shots) to a windmill-type rig or upright rotating fan, shoot it clean. Then shoot a stationary, still bottle on greenscreen. Composite the two in post. Can mark up the monitor with small bits of tape to align the two.

I'm quite excited about the whole idea actually, been watching too much Scrapheap Challenge (Junkyard Challenge?), an English TV show where 2 teams make monster trucks and aeroplanes out of nothing but junk.

Sorry, I'm not one for small posts…

Cheers all,

Jim Cox

I think you're killing yourself attempting to do this completely in camera. Simply shoot a shot of a bottle static on greenscreen. Then rig a camera overhead on a hi-hat or other Lazy-Susan rotating plate. Use a Weaver-Steadman head or even a simple L-plate to make the camera point straight down and use the head's balancing adjustments to make sure you're pointing straight dead down the lens. Spin away and composite in post. You can support this rig with a static goalpost setup rather than all the double-dolly you were thinking and all it's associated flexing and tolerance issues. Some simple scaffolding might even be big enough. And the perfect head to use would be a geared one so that you could use the wheel to make the speed nice and regular, maybe even with a motor drive if you wanted to get really spiffy.

I don't think I'd want an actor sitting under a camera rigged from a pair of dollies spinning around with a bottle on wires suspended in the centre. I sense severe pain somewhere in there.

Mitch Gross

Rig the camera overhead, locked off, looking straight down. Put a largish piece of flooring on a spindle of some sort and attach the bottle to top of the spindle. With the lens over the spindle axis, spin the flooring.

Hopefully you don't have any obvious shadows that give away the fact that the bottle isn't spinning. Maybe you mount a light source to a corner of the floor so that bottle shadow moves appropriately.

This assumes, of course, that you don't have to see any people in the shot. I wonder if you could shoot a straight down shot of the people on blue/green screen and then rotate them around the bottle in post? You'd have to shoot a nice big plate, maybe on Super 35 full aperture. Maybe that would be too messy, having to matte them on top of the floor and fake motion blur at the same time.

You could always attach them to the floor very quickly with a screw gun.

Art Adams, DP
Mountain View, California - "Silicon Valley"

All sounds very complicated to me.

In the old days I would have done a shot like that very simply with a dove prism mounted on the front of the lens...OK on 35mm with an 85mm or longer lens.

Maybe some of the older rental houses still have one.

David Samuelson

>The Revolution Lens or similar products can rotate marvellously on the >nodal axis without having to move the camera itself. Speed is very >easily controllable and the camera would be stationary.

Good solution, although you lose any sort of interactive lighting effect on the bottle that would result from it actually spinning.

Art Adams, DP
Mountain View, California - "Silicon Valley"

The Revolution Lens or similar products can rotate marvellously on the nodal axis without having to move the camera itself. Speed is very easily controllable and the camera would be stationary. All you need is a Jib arm to create the distance between floor clearance and subject. If your budget doesn't allow for that, there is an affordable device called "Roundy-Round" that is a motorized (speed controllable) head that spins the camera itself on its nodal axis if set-up correctly. It is a cheap rental but a pain to balance and in my experience tends to be a bit shy on set besides being heavy.

Usual disclaimers apply.

Florian Stadler,

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