building a cable cam

[Andzei Matsukevits]

I saw a movie with a lot cable cam footage, and it looked really great. So is it possible to build cable cam on your own? Any tips, links etc?

[Marcus Marchesseault]

I am going to try building a cable cam. I have some 4" nylon laundry pulleys and some cargo straps to tighten rope to trees. I have some polyester (not poly/polypropelene) rope which is very strong and stiff. I think nylon rope would stretch too much and "poly" rope is just junk for everything but water-skiing ropes (since it floats). I plan to try two ropes strung one above the other with the camera carrier attached between the parallel ropes by pulleys. This way, the camera will be prevented from flopping around too much. I have not started building, so I can't give you any real advice. I would love to hear from other shooters!

Marcus

[Meryem Ersoz]

there's a pretty good picture of a guy with his camera swinging on a cable cam at:

http://www.thecollectivefilm.com

(once you enter the site, you need to click on the "teaser" menu to get the picture, on the far right).

do you know any climbers? they could probably rig a bomber cable cam for you. or ask darcy wittenburg, the guy who i think is pictured on the cable cam in the "teaser" menu....

and while you're at it, buy the film. some of the best cable cam footage i've ever seen.....some truly impossible shots.

[Dean Sensui]

You'll have to consider the amount of tension needed to keep the cable from sagging too much. Also, Nylon, polyester and other such ropes have a considerable amount of stretch. It would be better to use steel cable or something like Spectra line that won't stretch much.

Figure out how much the camera package weighs and understand that the breaking strength of the line has to be significantly greater as it has to withstand the tension to prevent sagging as well as the weight of the camera.

And as for the pulleys, remember that with all that tension the pulley cables need to hold up under the strain. Especially the pulley bearings. And the pulley wheels need to tolerate the pressure of the line without eroding.

It's one of those ideas that look simple enough until you actually start to build it -- there's more to it than meets the eye.

[Andzei Matsukevits]

im thinking about motor now, what u guys think if i will put remote controlled car(toy) as the motor?

[James Ewen]

This is a classic wildlife rig.
The wire cable, snaps and fasteners used for rigging boat masts are suitably heavy duty and durable for the job of the zipwire, I agree with Dean that you need tension.
The camera cradle/pulley rig is more difficult, go for the largest wheel radius practical. The best rigs have two wheels to ride the wire, get your local friendly enginner to make an Aluminum cradle to support the camera and voila...flying tracking shots.
Apropos the motor, no idea experience myself but people have done similar before.
Test it with a brick before your expensive camera
The masters at this kind of thing are www.canopyaccess.co.uk

James Ewen
DP
Earthmedia imaging and film
Mozambique

[Jacques Mersereau]

I rigged a cable cam and would suggest using at least 1/4" coated
aircraft cable (2500 Lbs). Buy a heavy duty ratchet strap (10,000 LBS.)
to tighten the wire. You should also plan on purchasing a
SWAGING TOOL kit (huge crimper and sleeves) to make loops. I double up
on the crimps as I had single crimps give way. I think
www.proadv.com sells the Ferh swaging kits.

You will also need quick links or shackles to rig it all. I would also suggest
buying petzle or some other very smooth pully(s) as the cheap ones
start to chatter which induces lots of vibration.

We flew a Panasonic EZ30 300' and had good results, but you should also
plan on underslinging a weight to help stabilize the camera.

[Meryem Ersoz]

oh, you want an *unmanned* cable cam, i get it. in that case, check out http://www.superflycam.com/ for pictures and examples.

[Ryan Spicer]

Let the buyer beware: I am not an engineer, nor have I ever built a cablecam, but I have scratchbuilt my own electric-powered pan/tilt jib and a variety of other gizmos for DV, and once upon a time when I was a teenager, I rigged a 100' zipline in my back yard. Worked great until the crappy cable I was using snapped, which hurt.

Getting a motor beefy enough to move your carriage along the cable will be pretty expensive, and noisy, and power-hungry. Depending on the application you're planning on using it in, you might want to consider rigging the cable with a slight downward grade and then using a gravity as the main propulsive force, with a brake to control speed, rather than a motor. If you run a secondary cable from the cradle up to the top end of the line, then down to ground level, you could put the brake at ground level (no need for remote control for that aspect), and just crank the cradle back up after a run. I have no idea if this is an accepted way to do things, but it makes sense to me, at least if you're not going to have a human up there on the cradle.

One thing you might want to be aware of when designing your remote control mount for the cradle is that spinning cameras do have appreciable inertia. I found that if I made any quick start-stop pans/tilts with my 9' aluminum jib, the whole arm would vibrate noticably. I imagine this would be worse with something hanging from a cable and only fixed in one axis. I have no idea how people deal with this, and if anyone wants to tell me, I'd be curious to find out. :)

Cheers,
Ryan Spicer

[edit] was thinking about my comments on my jib and vibration from inertia; clarified my statement.[/edit]

[Andzei Matsukevits]

hm, its interesting idea, thanks dude!

[Meryem Ersoz]

you might get some ideas from this site:

http://www.slacklineexpress.com/kits.htm

they have a lot of direct links to pulleys, ratcheting tiedowns, slick rope, etc.

[Marcus Marchesseault]

I didn't see these posts before I went and bought some 3/16" cable. It seems that I hit upon the basics anyway. I bought the appropriate ends (with triple clamps) and some 1200lb straps to hold it to trees. This cable cam is NOT designed to hold people! I chose the cable because I figured it is less flexible and the plastic covering should make the 4" pulleys slide more smoothly.

The hard part will be to build a car for the camera, but it is certainly not insurmountable. I like the idea of an R/C car as a motor, but that is more complicated than I want to deal with now. I just want a rig that I can wire up and have inexperienced operators make smooth tracking shots.

"Also, Nylon, polyester and other such ropes have a considerable amount of stretch."

Polyester rope is a bit different. It has very little stretch. The stuff I have is so strong and stiff that it would probably be dangerous for climbing. A fall with this stuff would break your neck. It would stop you so fast it would be almost as bad as hitting the ground. "POLY" rope is the flexible junk rope that is so common in hardware stores these days. Nylon is good rope, but very flexible. If I only wanted a short rig (under 20'), I would probably stick with polyester since it is easier to change lengths with rope than with cable. My 40' of cable should do the job supporting my VX2000...I hope...

[Andzei Matsukevits]

actually remote controlled car would not be powerful enaugh. Im thinking about garage door opening motor, it is controlled by remote, but it is really expensive...

[Adam Bray]

Why not pull the cam with a fishing rod/reel? I do some offshore fishing and know that a lot of offshore reels come with variable speeds that could pull the cam along the line at a pretty fast rate and can reel in fish that weigh hundreds of pounds. So a 20 pound camera would be no problem. The reels can also hold 300+ yards of line. So theoretically you could have a 300 yard cable cam shot if you wanted.

[Derek Weiss]

I'm working on a system now to augment my current helicam setup. This is working very well so far. It has only pan/tilt and 2.4ghz downlink set up for remote monitoring. Takes two to operate. One for pan/tilt, and one for speed control. Runs on remote control radios.

This brief clip is pre KS2 gyro. With the KS2 gyro, there is absolutely no camera shake. I have done 300-350 ft shots successfully. I will be doing some 700 foot shots in the winter of 07/08. My system was designed to be light, as I have to haul it around in the mountains to set it up. I am 'flying' a Sony FX1 and a Pany SD1 on it. It works better with the heavier weight of the FX1.

16mb-WMV
www.pitonproductions.com/RandomVids/Cablecam.wmv