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Inertia and Weight Distribution


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#1 Nicholas Davidoff

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Posted 30 July 2009 - 01:09 AM

Just curious how some fellow steadicam operators like to set up their rigs in regards to inertia. More specifically, the distribution of weight at the bottom of the sled.

As most of us know the distance between the monitor and rear battery module dictates how much inertia feedback you receive from the rig. The monitor further forward and the batteries further back creates a greater distance between the two and thus more inertia and stability. The monitor and batteries tighter to the sled creates less inertia and thus a more maneuverable rig with a smaller footprint. Personally I've found I prefer a tighter setup to create a more agile rig which must be handled with a lighter touch. When I spread the bottom weights too far apart I find I have to muscle the rig that much for control, especially through tricky moves. However, if I'm flying a very long camera, like an F900 with zoom lens and rear mounted battery, I spread my monitor and batteries further apart to better match the greater camera inertia I have on the top stage.

I had a conversation once with a veteran operator who told me "I'll take as much inertia as I can get", and this got me thinking. I know that not all rigs have this kind of adjustability, but for the ones that do, I'd love to hear some thoughts on this subject. Do you prefer more or less inertia? Do you adjust it per camera or style of shooting or do you leave it fixed at all times? How much inertia is too much?

Thanks for your input,

~ Nick
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#2 RonBaldwin

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Posted 30 July 2009 - 01:47 AM

I think we are required to replicate a dolly more often than not, so the more stable our rigs the better. Sure, if I was doing a music video or something that requires fast movement I'd compress the rig but I work primarily in the tv episodic/feature world where they want a dolly that bleeds. I like the rig to stay where I put it.

I have used one of Greg Bubb's extendable monitor brackets since about 2000 to push my TB-6 as far out as possible for more inertia as well as easier viewing. I recently got one of the tiltable Sachtler monitor arms to lower the monitor a bit as well -- this really helps with lighter monitors (Jens wrote about this bracket last year).

I fly a Pro1 sled, so my normal set up has all three batteries almost all the way back (that's 7 lbs of batteries behind the post) and the TB-6 about 6 inches in front of the post. Some don't like a really long sled but to each his/her own.

rb
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#3 chris fawcett

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Posted 30 July 2009 - 07:22 AM

Hi Nick,

I like a lot of pan inertia too, that's why I love the new Accessory Balace Weighs system http://www.steadicam...showtopic=10286

But when working with a long camera, the pan inertia is already there. I don't understand your need to 'match' it below.

All the best,

Chris
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#4 RonBaldwin

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Posted 30 July 2009 - 10:51 AM

about having a long sled with a long camera -- when it comes to slow moves and fast walk and talks, too much inertia is not a bad thing. If you have to do whips or fast panning then it may not be a good idea.

rb
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#5 Charles Papert

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Posted 30 July 2009 - 12:27 PM

I'll echo Ron's sentiments exactly. I too have that thought in the back of my mind: "if I'm shooting something like a music video I'll tuck in the rig" but in reality, I never do it. Even when whipping, having that extra inertia helps prevent kickback at the end of the whip, even though it requires more force to start and stop--it's rare that one is working with a rig so inert that it is a hardship to apply that extra force.
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#6 Alec Jarnagin SOC

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Posted 30 July 2009 - 09:23 PM

I don't like keeping the rig fully extended all the time because then I have no where to go when they put on a 135mm prime and I want to slow the rig down. So I usually keep the sled fairly extended but save some for special occasions. Like others, in theory, I suck it in for whip pans, etc but come to think of it, I don't (I think Charles hit it on the head).
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