DV Info Net

DV Info Net (http://www.dvinfo.net/forum/)
-   Stabilizers (Steadicam etc.) (http://www.dvinfo.net/forum/stabilizers-steadicam-etc/)
-   -   Overloading a Steadicam (http://www.dvinfo.net/forum/stabilizers-steadicam-etc/110359-overloading-steadicam.html)

Ted Spencer December 16th, 2007 10:12 AM

Overloading a Steadicam
I was wondering what the effect of overloading a Steadicam weight-wise might be. I expect to have my Pilot in my hands tomorrow, and to start digging into learning its use with my HVX200.

I just got myself into an HPX500 fantasy for a minute though, and it appears to weigh about 13 pounds or so with a lens and battery, which is 3 pounds over the recommended weight maximium for the Pilot. So...what happens when you attempt something like that?

Is it that you can't load on enough counterweights to balance it? Or that if you do the gimbal gets stiff? Or the arm?

In short, what might you be able to "get away with" if you break the weight limit rule, and what are the consequences of doing so beyond a certain amount?

Perhaps some of our experienced operators here can inform me (us) about this question. Thanks in advance.

Tom Wills December 16th, 2007 11:12 AM

Well, I can't tell you whether or not the Pilot sled will physically balance or be safe with a 13 pound load on top, but I've tested what happens to the arm when you max it out. Above 15 pounds (sled plus camera weight), the arm will need to be adjusted to max tension, and will not lift the sled to the middle of its boom range. If you then want to have it at the middle or upper portion of the boom range, you'll need to hold it up with your own strength (you won't be holding all of the weight, but you will be holding the "overage". It also may put unwanted stress on parts of the arm. I'm not sure on the actual affects on your operating or the arm itself though - so maybe someone more experienced can chime in too.

Also, that 13 pounds sounds a little light for a flyable setup. You could remove the battery to save some weight and power the camera off of the sled, but the snap plate for attaching it to anything will probably weigh 2 pounds by itself. It might just be a better idea to stick with your HVX for Steadicam work.

Jaron Berman December 16th, 2007 01:45 PM

Well, the Pilot no doubt has some safety margin built-in, but still. The arms are spec'd pretty close to their operational limits. If it's meant to max with a 10lb load, it WILL max with a 10lb load. On the Tiffen smaller arms, you'll find that everything is scaled for the load that was initially intended. Pins, bearings, etc... are all correctly sized for what they should carry, not overbuilt. If you wonder, "wow, how did they make this amazing arm so light?" That efficiency has a lot to do with building for the intended weight, and no more. Also, the vest was only meant to spread so much weight. At a certain point, it'll probably be VERY uncomfortable... more so than a much heavier rig on a much beefier vest.

So what happens on overload? I think there have been many posts about this topic in regards to the Flyer, but it's basically the same. First thing that happens - it gets very hard to balance. Then, the gimbal starts to break down, and either the balls become non-linear or they start carving checks into the ball races, essentially destroying themselves. Then (and worst) you may get catastrophic failure of the arm post or any number of joints which means - you don't know where, but something "pops" without warning, and the camera falls to the ground. Sure, it may look like it's holding fine when balancing statically on the stand, but think of the forces and accelerations you put on the rig when doing something as simple as walking.

If you don't mind replacing your gimbal, arm post, camera or any number of pieces, go for it! But, be forewarned - the rig was designed to do what they say it was designed to do, with very little overbuild. Even the flyer is a bit small for an HPX. My advice is - train on your camera. Get EXTREMELY good on your camera. Then, as bigger jobs come up, make friends with someone who owns a bigger rig, and start renting it when you need the added capacity. The beauty of something like the pilot is that it takes a very delicate touch to make it look good. Enjoy the new rig, and try to resist the temptation to overload it - use right tool for the job, and your reputation will thank you. Don't wanna be "that guy" who dropped the camera when his rig exploded.

Ted Spencer December 16th, 2007 02:27 PM

Thanks so much, Jaron. All good advice, duly taken.

Mikko Wilson December 16th, 2007 03:58 PM

The great thing is that the current range of Steadicam Arms very simply can't lift more than their specified limit.

As Tom said, when he puts over 15lbs on his Pilot arm, it very simply hangs below level, this is the sign that it's overloaded. At this time, the strength of all those components start coming into question.

And the various Steadicam systems are carefully matched amongst themselves:
If you can balance the pilot sled without the arm sagging, you are good. You can *always* add weight to balance the sled, but if it overloads the arm, then you have also overloaded the sled.

Same with the Flyer, once the arm can't carry the sled, then the Sled is over loaded.

That's why you don't want to mix-n-match the systems too much. You can fly a Pilot sled just fine on an Flyer arm, but you loose that "overload warning" that the correct arm provides.

I had a shoot recently while my Archer sled was undergoing some repairs, so I had to borrow a Flyer sled, and the configuration *just* overloaded the arm, so it wouldn't lift to level any more. I considered the shots, which where very gentle simple "walk-n-talk" shots, and decided to take the risk and fly it on my G-50 arm. I was careful, and it was fine - still within that "safety" margin, but at that point had I have been doing a lot of larger moves with large G-forces, I could have been asking for trouble with the sled.

Certain combinations are safe of course: basically using an over-sized vest never hurts, and you can't damage an arm from flying a too light sled for it, but you really have to know what the sled can take at that stage.

The HPX500 is really a camera for the Archer and larger rigs, though it probably will fly on a Flyer just fine in a limited configuration when stripped down.

Feel free to experiment with your Pilot, try all sorts of balancing options with the sled, but once the arm can't lift it any more, then you are in that gray area between "the sweet spot" and "trashed rig on the floor".

- Mikko

Tim Le December 16th, 2007 04:14 PM

I think the biggest problem would be overloading the arm. The springs are tuned for the stated weight capacity so from a performance standpoint, if you exceed the limit, you'll max out the weight adjustment and the arm won't fly at the right position. From a technical standpoint, if you go a lot over the weight limit, then there is a possibility something may break--most likely a spring or a part of the arm. If one of the spring goes...oh man, look out. I noticed Steadicam issued two service bulletins for the Flyer to help cope with heavy loads and both of them affected parts on the arm. So just using my engineering hunch, the sled and gimbal can probably take a few extra pounds, but I'd be more worried about the arm. Either way, I would never recommend exceeding the stated weight limit on any piece of camera support equipment.

Ted Spencer December 16th, 2007 04:50 PM

Thanks for your input Mikko. I note however, that both you and Tom mentioned 15 pounds as the point at which the Pilot maxes out, but as I understand it, Steadicam's stated limit for it is 10. So in practice I might expect to be able to exceed that by a few pounds?

With my HVX, it's possible that if I loaded it all up with some of the extras I plan to use, like a Letus Extreme lens adapter (which is quite heavy) and SLR lens (I recognize that shallow DOF is generally undesirable with a Steadicam, but just for argument's sake...), a pair of lav receivers, zoom remote and so on, that it could exceed 10 lbs by a fair bit.

So am I understanding correctly that, at least from your experience, I could at least *approach* 15 lbs pretty safely?

To be clear, in no way do I expect to be abusing the thing. I imagine that most (if not all) of the time I'll be using it well within the 10 lb guideline - an HVX, battery, 2 P2 cards, zoom remote...that's about it. But curiosity prompted the question.

I guess in my own case the proof is in the pudding - if it will balance properly and the springs will float it short of maxing them out I'm good to go. Right?

Jaron Berman December 16th, 2007 05:04 PM

Mikko and Tom are referring to the arm's payload, not the sled's. The arm tops out at 15lbs, but don't forget that some of that payload is taken up by the sled itself (approx. 5 lbs). Hence the recommended maximum camera weight. So your initial guess of a 10lb max camera is more in line with what I would expect.

If you're loading down the system that much, don't forget that with a little clever cabling, you can move some of your weight to the bottom of your sled. It's not the worst thing in the world to run cables from the front of the monitor up to the camera - unless you're doing a lot of switches, they should stay relatively free of your operation. I have not used that particular rig, but from what I understand, you can use some kind of lightweight batteries on the lower sled as opposed to full bricks? If this is the case, and you're scraping to make your HVX-35-audio-lens kit fit, you may try powering the lower monitor off lightweight batteries, and putting your wireless receivers where the brick usually goes. Run some XLR's up to the top of the sled by carefully taping them to the monitor, then a straight run up to the cam. Again, I don't know if this buys you any more capacity, but it should - perhaps enough to squeak by.

Be warned though - if you have the 35mm adapter on, you'll need some way to focus it. You could pre-focus, and then just remain the same distance from your subject the whole time (which limits your shots). Otherwise, you'll need a wireless focus setup, which adds pounds to the top. I know Charles was testing a new wireless focus kit recently, you may try getting his input... I'm not sure how much the system weighed, but even the fantastic Bartech adds a couple pounds, and its pretty lightweight.

Ted Spencer December 16th, 2007 05:20 PM

Thanks again Jaron. I have in fact ordered the AA battery powered Pilot, so maybe that saves a few ounces right off the bat (tery?) ;).

Using the 35mm lens/adapter may be as much about matching the look of other non-Steadicam shots with it than DOF considerations. They do change the whole visual result of the camera quite a bit. If I can put it all on the Pilot, and if I've got enough light to step the lenses down sufficiently, then I can keep the look of the adapter/lens without finding myself in shallow-focus handcuffs. Hopefully... : )

If not, then I guess I'll be mixing adapter and non-adapter footage. Hopefully that won't present too much of a problem in editing and color grading.

Charles Papert December 17th, 2007 01:22 AM

The focus system that I tested was not to my approval, enough so that I declined to put up a review of it. I found it literally unuseable. There are at least two systems that are threatening delivery within the year that sound much more viable, and still quite inexpensive, so assuming that at least one of them emerges this particular one will not merit much attention.

Regarding the smaller Steadicam arms, I have heard whispers that certain Flyer arms will take significantly more payload than they are nominally rated due to variations in the springs, which is likely the same case with the Pilot arms. However it is true that the surrounding parts may fail before this is relevant.

Ted, a few years back I was shooting exteriors with a Mini35/DVX100 and when the light began to fail, pulled the camera off the adaptor and kept shooting. Had very little problem matching the footage, in fact I can't tell any more which was which. And I had the remote focus technology in play so I wasn't hamstrung with stopping the lens down, nor did I have a lightweight rig with weight restrictions. Given all that you are juggling, it sounds like flying with the camera as-is will be the smart way to go,you'll be able to work faster and with less restriction.

Ted Spencer December 17th, 2007 08:59 AM

Thanks Charles.

I'll definitely be doing extensive testing of the adapter issue alternatives before any serious work gets undertaken. It would seem that careful color grading should be able to overcome most if not all noticeable differences in appearance with and without a 35mm adapter. In some cases, as you indicated, it might not be needed at all. We'll see...

The adapter I plan to use is the Letus Extreme, and I will likely be acquiring new Zeiss primes (28, 50 and 85mm). It's my impression that the PS Technik mini35 is probably a bit faster than the Letus, but not much. Hopefully I'll be able to get everything to live happily together.

I'll try to resist the temptation to break into that Turtles song once I do...

Ted Spencer December 19th, 2007 06:30 PM

Just a quick note on my own question...

I received my Pilot (woohoo!) and first of all, it is really, really impressive. I think it's going to be everything I hoped for.

But on the overloading question, I noticed that it appeared to come with the arm springs fully or near-fully tightened. In order to fly my stock HVX200 properly with just a battery (~6 lbs.) I had to loosen them a *lot*. A *real lot*...

So my early impression, if that's any indication of load carrying capacity, is that the rig will probably take a good deal more than 10 lbs.

Further testing to follow...

Jaron Berman December 19th, 2007 07:08 PM

The beautiful thing about Steadicam's new arms is that they are isoelastic. Part of this feeling is the way that the springs themselves are supported within the arm, making them behave non-linearly. I've had the same feeling with both of my steadicam arms - like I had a lot more capactiy than advertised. Once loaded, however, you start using up those threads pretty quickly, and you'll find that the ratings they give are pretty accurate. However, Jerry did mention that a couple of arms "got away" with a fair amount more capacity than intended... so you may be on of the lucky ones! Only one way to find out. Keep loading till the arm won't support it anymore. Then weigh it! At the point that the arm just sags under weight, you should be in no danger of breaking anything. Much beyond that, however, and the failures I've heard of (from Peter Abraham, a man who enjoys breaking a rule now and then) have been pretty gnarly. Even he suggested not going much beyond the arm's capacity. But I am curious to know if you got one of the lucky rigs, and if so what it can take.

All times are GMT -6. The time now is 04:17 AM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2018 The Digital Video Information Network