Powering both FS700 and O7Q with one battery

Colin, agreed. It's almost time for Charles to chime in ? Charles are you there? Cough... Steadicam .. Cough. I was so impressed to see him in this forum a few weeks back... I've yet to try my 7q on my flyer and send it out via teradek clip. Anyone else tried their 7q on a steadicam yet? Weighs more than a hyper deck :)
 
Stability (rotational inertia) is "Distance from CofM" Squared X Mass

So if you double the spread, the stability increases by four
If you double the mass the stability doubles

I'm not denying that high mass adds to stability, just one can get better increases in stability by intelligent use of position of mass.

S
 
It's pretty clear that striving for stability by adding mass has a limited amount of gain, with diminishing returns. It would also prove helpful to hire a gorilla for an operator, or just go to the gym and work out. Agree that intelligent positioning of mass is needed; and, requires some thinking and planning. In the professional work I've done around camera mounts(and these were cameras with very long focal lengths, where the need for stability increases dramatically) the goal is to increase mass while keeping it all as close to the COG as possible. The two considerations for motion control are both for translation and rotation. And, indeed, one wants the COG as close to the center of rotation as possible, keeping the moment of inertia as low as possible for rotational performance while increasing the mass for translational stability. The missing piece in this discussion is the effects of harmonics, i.e. resonance of mass in cyclic motion. Increasing mass reduces the frequency of the cyclic motion, as I said, above. However, the work done in accelerating mass into motion increases as the mass increases. Tuning a dynamic system involves mitigating system harmonics with damping and spring constant adjustments. One may never totally eliminate unwanted motion, but, it can be reduced and controlled. Friction is a natural damper.

Since it appears that you guys are well versed in the principles of dynamics and motion, I'll risk adding a bit more detail. A steadycam is a six degree of freedom (DOF) system, meaning a camera on a platform like this can move in all three directions, x,y,z in a cartesian coordinate system. That is to say it can translate and rotate about any one of these axes. The dynamic equations of motion apply to any one or all of these 6 DOF's....moments of inertia and stability are dealt with independently for each DOF.

Interesting sidebar that my steadycam work is like my golf game. Pretty good on the front 9, then abhorrent on the back 9 when my back begins to hurt...:)

So, bottom line, make it light and keep the mass center as close in as possible for run and gun, change of position. Make it heavy for stability. Competing performance needs, and every shooter just has to find that most comfortable of an uncomfortable situation. (Looking at gyro stabilized camera platforms....interesting that an optimized gyro stabilized system is tuned to match the moment of inertia and mass of the camera platform)
 
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cuervo said:
So, bottom line, make it light and keep the mass center as close in as possible for run and gun,
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Wrong. You want light with the mass spread out.

When you run down the road with a ladder it tends to point straigt, running with a canon ball of equal mass to the ladder will exhibit far more angular deviation. Make a rig like a ladder not a canon ball.

A (movi) gimbal the motors must apply 'work' to keep the system stable so minimising inertia is indeed correct as the 'work' provided by the puny motors does more - that is the opposite of handheld where your 'work' (aka shake) wants to have minimum transition to the camera the effect of 'work' should be minimised by maximising inertia.

For a movi you want a canonball rig.

As for long lenses and vibration - indeed a low resonant frequecy is good - mass. But for handheld HF vibration is not really a problem.. the body is great at vibration reduction. Grab a running motor with one hand and the other hand will not start to vibrate as the flesh muscle etc damp perfectly. If you have ever done shoulder mount from a plane/helo and the camera came into direct contact with the airframe you will be aware of how much HF damping the body provides..

S
 
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morgan_moore said:
Wrong. You want light with the mass spread out.

When you run down the road with a ladder it tends to point straigt, running with a canon ball of equal mass to the ladder will exhibit far more angular deviation. Make a rig like a ladder not a canon ball.


S
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Good feedback, Sam. My entire work in this field is tripod/gimbal mounted. Aircraft mounted, small angle of view cameras are a unique environment. Vibration is very high frequency and tend to blur the image rather than produce low frequency translations. I have very little steadycam experience. But, it would seem intuitively obvious that the operator wants stability(ie add mass or MOI), but, by the same token, doing work to rotate or translate will requre more and more muscle work as the MOI or mass increases, therefore tiring more quickly.

So, if I was going for a short (<1 hr) run and gun interview, I'd load up with weight. If I was gonna be shooting steadycam all day long, wow, I'd go as light as I could. And, BTW, MOI and mass are not competing parameters.

A movi is a very simplistic gimbal system. The complications of building a good stable platform system require in depth FEA analysis and a considerable amount of tuning for the real world, as computer programs only approximate reality. Movi is also used for remotely operated systems, which introduces a whole new performance parameter related to acquisition, pointing and tracking without operator feedback to the control system. The dynamic system can be extremely stable, but have a TON of unacceptable motion because the operator is trying to point and track....control system dynamics.

But again, you have considerably more expereince than I in this particular application, so I demure to your opinion. Thanx, again.
 
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Good to think both ways, Ive struggled with 135 mounted on a vehicle - I can see for that I need to work on canon ball not ladder!

S
 
cuervo said:
Interesting sidebar that my steadycam work is like my golf game. Pretty good on the front 9, then abhorrent on the back 9 when my back begins to hurt...:)
Click to expand...

If you're back is hurting, you're doing it wrong (NB, I know I sounds like an arse saying that, but I'm not trying to be I'm just trying to provide feedback). The Steadicam vest is designed to translate the weight of the rig from from the arm to your hips, not your shoulders. When you get tired, it should be your legs that get tired, not your back. If you're back is hurting after a while operating then there's likely to be a couple of things wrong:

1. The vest isn't tight enough on your hips. Honestly it should be so tight it almost hurts, if you feel the weight upon your shoulders at all, it's not tight enough.
2. The mounting block is adjusted wrong. You need to adjust the screws on the arm (the one's that sit in the block) and the screws on the mount (the ones at the front) so that the rig will hang comfortably by your side as you stand comfortably straight (or with legs slightly bent), without having your hands on the rig. If you try this and the rig moves away from you, adjust the appropriate screw until it hangs where it should. If you don't do this you'll either be unconsciously leaning/tilting your hips to compensate - or all be fighting the rig the whole time.

Seriously, try making those adjustments. I can tell straight away if I've not got the vest right as I start to get back pain. It then goes once I take the time to make the right adjustments.

Same goes for hand held. If my back hurts, I know I've not take time to balance things properly...
 
Another note on shooting with a Stedicam rig. Of course set it up properly with dynamic (spinning) balance correct. There are many good videos and pdf instructions on how to do this.

But most important is to learn to steer the rig by moving your upper body. Neutral tends to be leaning back just a bit so the rig does not pull you forward and assert pressure on your back. Then to start moving forward just lean forward a bit and it automatically will feel right, to stop lean back a bit, same with right and left. Just get used to it and until it becomes second nature, and all of a sudden you don't get tired at all, even with a heavy rig.

I see a lot of shooters new to Stedicam sort of leaning forward and struggling with their back and arm muscles to hold the rig back. It should just float and be balanced from your hips, a lot like skiing with the weight in the middle of the ski. You get more control and less fatigue, to aggressively move lean in the direction you want to move and balance, but your hands should only use a very light touch on the rig. Unless you are simulating an earth quake or explosion...
 
Thanx for the feedback, guys. I'm off to practice with my Steadycam. I do have the tendency to lean into it, even tho I have it tight around my hips and neutralized with the adjustment screws....good thing to remember.
 
Essami said:
OK, still undecided on the plate for the Sony NP-F batteries. The Westside plate is the handiest but it's 138 dollars and Ill have to pay taxes and vat on top of that when I order from USA so it's very expensive.

Then there is this: http://www.ebay.com/itm/171053633303?_trksid=p2055120.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT that you could wire to a Convergent Design flying lead cable. Would that work?
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Ug, don't use that. Exposed leads, no way to mount it to the Odyssey, and no mechanical clip so the battery will just fall out.

There are many options for mounting Sony L-series batteries: Convergent Design (now in stock and shipping to dealers), Nebtek, Westside AV, and I believe a version from Hawk/Woods as well. The CD version is only US$75 list and it is prewired for the Odyssey. How cheap do you expect it?
 
Mitch Gross said:
Ug, don't use that. Exposed leads, no way to mount it to the Odyssey, and no mechanical clip so the battery will just fall out.

There are many options for mounting Sony L-series batteries: Convergent Design (now in stock and shipping to dealers), Nebtek, Westside AV, and I believe a version from Hawk/Woods as well. The CD version is only US$75 list and it is prewired for the Odyssey. How cheap do you expect it?
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75 USD is OK with me, no problem, but Im trying to find an alternative to the CD plate as it's so big and get's in the way of the mounting systems I have, Id much prefer the Westside one as it takes less space. It's a little bit more difficult for us in EU to source parts from all over the world as shipping, taxes and VAT adds to the cost and suddenly you're paying a few hundred extra for everything. :(
 
Hey Mich. Quick question : is it possible to et an extention cord to your power cable?
My situation is this: I bought the westsideav sony L battery plate, but I'm not mounting it on the odyssey, but instead on the camera itself - it gives me way better stability - only problem, the power wire going from the plate to the odyssey is just on the short side, so a simple short extention cord (female - to male kinda thing) would be great, as i'm not so keen on fiddling with the wires myself.
 
I can make an extension chord if you like. But this is expensive. I have both Nano connector ends in stock. It is over $50.00 just in parts.

Or you can send me the plate and I will exchange it to one with a longer chord. Just for shipping costs.

PM me or call me. cel 603-387-4921
 
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tscav said:
Hey Mich. Quick question : is it possible to et an extention cord to your power cable?
My situation is this: I bought the westsideav sony L battery plate, but I'm not mounting it on the odyssey, but instead on the camera itself - it gives me way better stability - only problem, the power wire going from the plate to the odyssey is just on the short side, so a simple short extention cord (female - to male kinda thing) would be great, as i'm not so keen on fiddling with the wires myself.
Click to expand...

instead of soldering a new cable or twiddling with an extension you could ask Olof to make you a second plate with a longer cable. I ordered a second one too as I damage the cable when mounting the hot shoe. Just the plastic part with the cable, not the metal part.
 
Clermond said:
instead of soldering a new cable or twiddling with an extension you could ask Olof to make you a second plate with a longer cable. I ordered a second one too as I damage the cable when mounting the hot shoe. Just the plastic part with the cable, not the metal part.
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But a new plate is 100$ ...adding shipping costs and 12% customs as I live in Europe - surely a piece of cable would be cheaper - if it exists. Also I'm my second plate from westsideav since the first one had the holes in wrong. But really: Nobody makes extention cables? Is the Flying lead (bare wire pigtail) power cable to Odyssey7Q that CD sells, not female in one end?
 
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Essami said:
75 USD is OK with me, no problem, but Im trying to find an alternative to the CD plate as it's so big and get's in the way of the mounting systems I have, Id much prefer the Westside one as it takes less space. It's a little bit more difficult for us in EU to source parts from all over the world as shipping, taxes and VAT adds to the cost and suddenly you're paying a few hundred extra for everything. :(
Click to expand...

I bought from Westside AV and it went really smooth. Helpful and willing to do that little extra to get you what you want. I might have been lucky but I didnt have to pay any taxes when I bought from Westside :) N I live in Sweden
 
tscav said:
But a new plate is 100$ ...adding shipping costs and 12% customs as I live in Europe - surely a piece of cable would be cheaper - if it exists. Also I'm my second plate from westsideav since the first one had the holes in wrong. But really: Nobody makes extention cables? Is the Flying lead (bare wire pigtail) power cable to Odyssey7Q that CD sells, not female in one end?
Click to expand...

tscav, Did you see my reply above:

I can make an extension chord if you like. But this is expensive. I have both Nano connector ends in stock. It is over $50.00 just in parts.

Or you can send me the plate and I will exchange it to one with a longer chord. Just for shipping costs.

PM me or call me. cel 603-387-4921

I can also make you just the plastic plate and the longer cable for $75.00. That is about what the extension cable would cost, then you would have a spare.
 
tscav said:
But a new plate is 100$ ...adding shipping costs and 12% customs as I live in Europe -
Click to expand...

I live here in Germany and didnt have to pay customs nor VAT for a 75$ piece. Got it with standard economy shipping within 10 days. Great service from Olof & Sharyn! +1
 
olof said:
tscav, Did you see my reply above:

I can make an extension chord if you like. But this is expensive. I have both Nano connector ends in stock. It is over $50.00 just in parts.

Or you can send me the plate and I will exchange it to one with a longer chord. Just for shipping costs.

PM me or call me. cel 603-387-4921

I can also make you just the plastic plate and the longer cable for $75.00. That is about what the extension cable would cost, then you would have a spare.
Click to expand...

Good idea Olof. I'll have a think and send you a PM then alright. Thanks:)
 
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