Jump to content



Photo

adding weight for balancing


  • Please log in to reply
22 replies to this topic

#1 kes

kes

    Advanced Member

  • Members
  • PipPipPip
  • 37 posts

Posted 04 August 2004 - 05:46 PM

Dear all,

Doing mainly tv work I hardly ever face the problem of having a much heavier front than the back of the camera, and so when a commercial or video clip job comes ( Sony 790 ) I always face some difficulties balancing the rig....
For example : Soon I have this Sony 790 job with Angenieux lens, matt box plus filters and a heavy M-One motor in front while only a light Li Ion battery on the back. Since in this setting the front is so much heavier I try to add more weight to the back by replacing the Li Ion battery with the huge and heavy Pro Pack, by mounting the Bartech AND the video transmitter at the back as well just on or by the Pro Pack battery... But hey, that is not enough ! the front is still heavier and the camera c.g. still does not reach the mark I am aiming at - .75 inch to the rear of the centerline of the central post ( I never do dynamic balance as I am too lazy and because I have no time as they always ask me to be ready in little time, and so the least I can do is to place camera c.g .75 inch to the rear and start balancing by moving the battery and the monitor - than I know the rig is roughly in dynamic balance ? )... And so I keep adding weight to the back in a form of small cube of metal until I finally happy.
Now I want to set my 3-4 seconds drop time but, ahem, now the bottom of the sled is much lighter than my extra heavy camera I am not able to get any drop time, not before I will start adding more weight to the bottom of the sled, again adding some more useless bits of metal just to be able to get the desirable drop time.
I must admit I am in a very good shape and so a heavy rig is not a problem but for a long and demanding day it might be an issue, also to improvise so much with moving weight is really frustrating and take some production time.
All I am wondering is if in a shot which does not include a fast pan dynamic balance is all that important ? Will you choose to operate without all the extra and unnecessary weight but sacrifice dynamic balance by not placing camera c.g. where you need it to be ?
I will be very happy to hear how you deal with situation like this.

Regards to all
Kes
  • 0

#2 Eric Fletcher S.O.C.

Eric Fletcher S.O.C.

    Advanced Member

  • Sustaining Members
  • 2922 posts
  • LA, Ca

Posted 04 August 2004 - 05:59 PM

If you know the cameras CG then why don't you have the mounting dovetail centered under it? You should never have to shift parts to get the dove tail in a favorable position. Even when I flew the "Sony Valdeze" (43" Long Sony 900 HD camera with Telecast Fiber Box) I NEVER had a balance problem and Never had to change out the configuration of my rig.

Your top to bottom problem is cured by raising the gimbal and Lengthening the post.

Out of curiosity what is your experience level and have you taken a workshop?
  • 0

#3 RonBaldwin

RonBaldwin

    Advanced Member

  • Sustaining Members
  • 2351 posts
  • Los Angeles

Posted 04 August 2004 - 06:45 PM

Eric is right...you should be able to get the plate in the right spot. If for some reason you can't, you could buy a longer plate or have an intermediate plate made. I don't know what rig you are flying, but you could add a battery to the bottom of your sled -- so it's not just dead weight. I hate extending my post more than about 3 or 4 inches, so I usually throw on my record deck.

Ron
  • 0

#4 RobVanGelder

RobVanGelder

    Advanced Member

  • Sustaining Members
  • 919 posts
  • Bangkok, Thailand

Posted 04 August 2004 - 08:09 PM

Yes, Kes,
Not only you admit you are lazy, you sound like you don not know most of the basics behind Steadicam.

Do yourself a favor and take an afternoon to set up this camera and rig so it works perfectly together.

If you start being "lazy" in your setup how can you expect any good results afterwards?
This attitude can hit you back very hard!

Rob van Gelder, Bangkok, Thailand
<_<
  • 0

#5 KarloTomic

KarloTomic

    Member

  • Members
  • PipPip
  • 29 posts
  • Toronto, Ontario

Posted 05 August 2004 - 12:31 AM

Hey Kes,
What rig are you flying? With a video background you shouldn't have any problem balancing any of the Sony HD's from the CineAlta on down since it's the same as any of the BetaSP's plus a few extra toys, but thats why your dovetail slides back and forth, personally I'm a huge fan of the Sony HD's and find that once mounted, can be balanced out withen 3 minutes including dynamically.
  • 0

#6 kes

kes

    Advanced Member

  • Members
  • PipPipPip
  • 37 posts

Posted 05 August 2004 - 01:56 AM

Hi,

I feel a bit fool to ask what I did as it seems so clear to you but I think I did misunderstanding some of the basic issue in steadicam, even when I have some unlimited access to the Elite. Unfortunately I could never take a workshop although I always think I should, but as always in life things are not always that black and white and you do not do what you should but rather what you can or efford. I should have place my quastion under newbies and so I would probabely upset less people.

I perhaps misunderstood camera c.g. issue but after making a fool of myself I might as well carry on and explain the wrong way I find camera c.g. :

After screwing the dovetail plate to the Sony plate and attaching the camera and all accessorise and battery to the Sony plate I will now start to find center weight of the whole thing by placing a rod between a flat surface and the dovetail plate ( with the camera and lens on top ), now holding the camera I start rolling it on the rod back and forth until I find the center of the whole weight, than I mark it. This mark I thought is considered to be the camera c.g. , and this mark I thought should be about .75 inch to the rear of the centerline of the central post.
Now because the front is so heavy the mark I found is too close to the lens and so does not mater how far back I slide the dovetail plate in the dovetail carrier it is still a way too far forward. I hope it does make sense - the way I explained it not the way I do it of course.
I know top to bottom problem is cured by raising the gimbal and Lengthening the post but if the bottom is much lighter even if you raise the gimbel all the way it wont help.
I am not really lazy ( use the wrong word ) I just once read placing camera c.g. about .75 inch to the rear place you roughly in dynamic balance which I thought is enough. Not understanding how to find camera c.g. is a different mater.

Unless you do not make me feel any more fool than what I already feel please explain me where I was wrong and the best way to find camera c.g

Regards
Kes
  • 0

#7 Gustavo Penna

Gustavo Penna

    Advanced Member

  • Sustaining Members
  • 61 posts

Posted 05 August 2004 - 02:23 AM

ITS NOT THE ARROW !

ITS THE INDIAN !

A Workshop ASAP would be a great investment,
and also to start getting an idea of the elites potential.

Try to check the forth and aft balance on the rig while suported in the balancing pin, "with out" a camera on top.

The front (monitor) will be heavier than the rear (batery) = Not a balanced sled

IN FEW WORDS YOU WANT THE DOVETAIL STICKING OUT ALMUST HALVE OF ITS LENGHT TO THE FRONT OF THE BRIDGEPLATE THAT MEANS LITERALLY BELOW THE LENS
  • 0

#8 Brad Grimmett

Brad Grimmett

    Advanced Member

  • Sustaining Members
  • 718 posts

Posted 05 August 2004 - 05:28 AM

Now because the front is so heavy the mark I found is too close to the lens and so does not mater how far back I slide the dovetail plate in the dovetail carrier it is still a way too far forward. I hope it does make sense - the way I explained it not the way I do it of course.

Sounds like you need a longer plate. I've flown the F900 with the pro35 and S4's many times and I've never had a problem balancing my rig. Sure, it's long, and front heavy, but it's not too long to balance with a long dovetail plate.
Do you have a long dovetail plate? If so, it shouldn't be a problem. What kind of rig are you flying?
  • 0

#9 kes

kes

    Advanced Member

  • Members
  • PipPipPip
  • 37 posts

Posted 05 August 2004 - 06:13 AM

I am flying the Master with 25 cm ( 10 inch ? ) dovetail plate.

Kes
  • 0

#10 PeterAbraham

PeterAbraham

    Advanced Member

  • Sustaining Members
  • 902 posts
  • New York City

Posted 05 August 2004 - 07:00 AM

A hearty yes please, seek a Steadicam Workshop. Where do you live?

Having said that, let me add this. Nothing is gained here by smacking around the inexperienced folks here. I for one can remember the very first gig I did with my Model I. It was the week the rig arrived. I flew in the face of ALL better instincts and took a job to try to please someone I respected. It was a BL IV on a Model I. I added the round weights that came with my Model I sled and it still rolled upside down on me. ( My rig didn't come with the longer set of posts, although I suspect it wouldn't have worked anyway ).

I tell everyone I show a Steadicam to that when they buy the rig- or BEFORE they get into it, they need a Workshop. This sounds self-serving because I do a lot of instructing but we all know it's the truth.

Lastly, yes I did have a very long plate at one time. Brant had some "bongo plates" machined. These were hellaciously long plates. They did the job, we had some oddball cameras mounted up now and again and I never suffered the problem that we do indeed sometimes face- the camera cannot be balanced easily with a single plate. The bongo plates flexed sometimes but at least afforded us interface. The plate I have seen that is simply spectacular in terms of zero flex is Greg Bubb's new plate. You really could make one of those in an 18 inch length and maintain zero flex state. So, there are solutions out there.

Peter Abraham
  • 0

#11 PeterAbraham

PeterAbraham

    Advanced Member

  • Sustaining Members
  • 902 posts
  • New York City

Posted 05 August 2004 - 07:17 AM

I may not have been as clear as I might have wished in that post.

The Universal Steadicam Model I ( and perhaps Model II as well? ) came with weights. They were split collars made of steel. They were available specifically so that you could add dead weight to a Steadicam, in case the camera body weight exceeded the balance ability of your sled.

That was 1976. I owned one of those rigs ( although I didn't own it in 1976. )

Now it's 2004. The new and very lovely Steadicam Flyer allows for a second battery to be mounted on the bottom of the sled. The mount is "cold"-i.e., not powerwired into the sled. The mount is there so that the second battery can be used......as a dead weight.

So, let's not spend a lot of time bashing someone who is ignorant of Steadicam- but not perhaps stupid- for suggesting using weights. There are other systems that allow for a battery to be mounted and used for added amp-hours/weight but not used to double voltage from 12 to 24.

This is not an ideal solution but is hardly A) a new idea in Steadicam nor B) reprehensible on the surface. I took a hacksaw and cut off an offending bit of bracketry many years ago on a job in Santa Ana, California. Ugly thing, to take a hacksaw to a Steadicam accessory bracket. It let me balance the camera and lens, and do the job.

Lest we forget in our well-machined and perfectly anodized world, that this is the bottom line. We have to do the job. Who amongst us as never shown up on a gig and found a problem awaiting us with the camera? :)
  • 0

#12 kes

kes

    Advanced Member

  • Members
  • PipPipPip
  • 37 posts

Posted 05 August 2004 - 07:21 AM

Thanks Peter for your advise. I probabely do need a workshop and a longer plate.
I think what I did wrong was to attach the dovetail plate exactly under the Sony plate without ever change it regardless the camera weight - I use a Sony plate ( without mantioning the manufuturer ) which does not let you very easily to attach it differently. Than an hour ago I tried with a different Sony plate with so much more holes and so I managed to shift the Sony plate back, which mean now the steadicam dovetail plate sticking out 3" from the front just under the Sony plate. That way I managed to bring the camera even more back than I could before - easy thing but never thought about it as I always worked with the same light camera and the length of the dovetail plate was enough.

Regards
Kes
  • 0

#13 Alec Jarnagin SOC

Alec Jarnagin SOC

    Advanced Member

  • Moderators
  • PipPipPip
  • 1800 posts
  • New York City, USA

Posted 05 August 2004 - 09:44 AM

Kes,

Peter has great advice. It sounds like you found the problem - I was about to suggest this. I've been doing a lot of HD lately with the Panasonic camera (a lot lighter than the Sony) using both the CLA adapter and the Pro-35 adapter. Add a Zeiss Ultra-prime and motors and you have a very front heavy system. I've been able to balance it every time by having my plate stick forward of the Sony (Panasonic - same thing - actually using the Chrozeil on one of these jobs and it is a lot more rigid, but that is another topic). This works fine, BUT many dovetails will flex a lot in this situation causing a vibration in the image (depends on how long your top stage is, and how far your plate is overlapping the camera plate). By using the aforementioned XCS plate (Greg Bubb) this ceases to be an issue. Not sure if his plate works in a Master, but can't say enough good things about it.
  • 0

#14 kes

kes

    Advanced Member

  • Members
  • PipPipPip
  • 37 posts

Posted 05 August 2004 - 02:30 PM

Thanks Alec for reassuring me - I needed that.
Kes
  • 0

#15 Brad Grimmett

Brad Grimmett

    Advanced Member

  • Sustaining Members
  • 718 posts

Posted 05 August 2004 - 06:23 PM

Not sure if his plate works in a Master, but can't say enough good things about it.

The XCS plate does work with a Master. I have both and the plate is great.
  • 0




Engineered Cinema Solutions

BOXX

Wireless Video Systems

PLC Electronics Solutions

PLC - Bartech

SkyDreams

Teradek

Boland Communications

rebotnix Technologies

Betz Tools for Stabilizers

Ritter Battery

GPI Pro Systems

Omnishot Systems

Media Blackout - Custom Cables and AKS

IDX

Paralinx LLC

Varizoom Follow Focus