Balancing a glidecam !? at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > Support Your Local Camera > Stabilizers (Steadicam etc.)


Reply
 
Thread Tools Search this Thread
Old March 21st, 2009, 11:55 AM   #1
Trustee
 
Join Date: Sep 2006
Location: Kent UK
Posts: 1,397
Balancing a glidecam !?

Hi guys

I've just bought a Glidecam 4000 (main unit only at the moment). - I am trying to get this thing balanced out and I just can't achieve what I've seen others achieve in their balancing.

YouTube - Glidecam TEST!

If you watch this guy (from 25-35secs) he's throwing it from left to right/front back and the pillar stays vertical. I just can't seem to get my set-up like this !? In a stationary position its balanced and stands vertically but in motion things begin to sway. I've tried one more weight and one less weight at either end and the situation gets worse so I think I have the weight ok. Extension is about 8 inches. Camera is HD110.

Any pointers or advise much appreciated !?
Mat Thompson is offline   Reply With Quote
Old March 21st, 2009, 12:08 PM   #2
New Boot
 
Join Date: Apr 2008
Location: Italy
Posts: 18
Hi Mat,
you have to move the gimbal on the post to achieve a 2-2.5 sec. drop time. If this is not possible you have to distribute the weights on the stage and on the bottom of the sled to achieve the correct drop time.
Amedeo
__________________
Amedeo Fabroni
www.ciakframe.com
Amedeo Fabroni is offline   Reply With Quote
Old March 21st, 2009, 12:31 PM   #3
Trustee
 
Join Date: Sep 2006
Location: Kent UK
Posts: 1,397
Hey Amedeo and many thanks for the swift reply.

The gimbal moves on the post ??? uhh....ok, how do I do this, it looks fixed to me !? 2 second drop time.....man this is way out then.
Mat Thompson is offline   Reply With Quote
Old March 21st, 2009, 12:40 PM   #4
Wrangler
 
Join Date: Jan 2002
Location: Los Angeles, CA
Posts: 6,781
The gimbal doesn't move on the post on the 4000. You have to alter the amount of bottom weight and/or monkey with the telescoping post to achieve the desired balance, i.e. drop time.
__________________
Charles Papert
www.charlespapert.com
Charles Papert is offline   Reply With Quote
Old March 21st, 2009, 12:49 PM   #5
Trustee
 
Join Date: Sep 2006
Location: Kent UK
Posts: 1,397
Hi Charles
Ahh ok...I didn't think it looked like it was meant to move. However that leaves me pretty stumped on how to get this drop time. At the moment it feels very camera heavy when it starts to sway BUT the drop is....well it certainly doesnt glide put it that way.

At the moment I have the weight in two piles and either end of the tray, tangent to the edges. 5 disks at each end !? Does this sound correct ?

Hhmmmm, puzzling
Mat Thompson is offline   Reply With Quote
Old March 21st, 2009, 12:55 PM   #6
Wrangler
 
Join Date: Jan 2002
Location: Los Angeles, CA
Posts: 6,781
OK, so your drop is....? don't leave us hanging!

To clarify: drop time is measured by swinging the rig to a horizontal position, letting go and counting how long it takes before the post swings back to a vertical position (it will obviously pendulum through that point repeatedly, but we only care about the first time). Make sure these are "real" seconds (one-missisippi!). If your drop is longer, remove weights; if shorter, add weights. Yes, with a standard setup you should keep the same number front and back.

If you find that the magic number is between weights, make it a little top heavy (which will result in a longer drop time), then extend the post a little bit and try again until you land at your desired drop.
__________________
Charles Papert
www.charlespapert.com
Charles Papert is offline   Reply With Quote
Old March 21st, 2009, 01:42 PM   #7
Trustee
 
Join Date: Sep 2006
Location: Kent UK
Posts: 1,397
Ok then....well i think about 1 second tops!


EDIT - RIGHT THEN !!! Now we are getting somewhere - Man this has taken some time. The key seems to be, get the drop time right first and then adjust the cameras position to achieve a better balance....or so it seems anyway!

I'd say the drop is just less than 2 seconds now....is this ok ?
It certainly seems better in motion, a lot more like the motion shown it that youtube link!

Another edit - HHmmm I'm not sure if it was just a flash in the pan or whether something has moved but its still swaying on my running test. Should these things really be that difficult to set up !?

Last edited by Mat Thompson; March 21st, 2009 at 03:23 PM.
Mat Thompson is offline   Reply With Quote
Old March 21st, 2009, 05:40 PM   #8
Major Player
 
Join Date: May 2008
Location: Bedfordshire, UK
Posts: 863
Hi Mat, I too struggled with my Glidecam, trying to balance it so i could throw it about. To get it like this you need a very low drop time, this means its neither top nor bottom heavy. however, truth is when using you wont actually be throwing it around like that, you will always have a hand on the post just below the gimble.

my optimal drop time is 3 to 4 secs drop time. remember were talking seconds, not count. so one one thousand, two one thousand and so on.

the reason the sled drops is because its everso slightly bottom heavy, whivh is fine because that is what makes it stable and your controlling hand can easily compensate. if it were very bottom heavy then it will have a short drop time and be harder to control.
Danny O'Neill is offline   Reply With Quote
Old March 21st, 2009, 06:11 PM   #9
Trustee
 
Join Date: Sep 2006
Location: Kent UK
Posts: 1,397
Hi Danny
Yeah I'm starting to see that. BUT, I seem to have gone backwards and forwards. I've read some info that says you should set the post to minimum, some to max. Of course with the post shorter its going to need more mass and vice versa. However I seem to do it, the resulting action suffers from sway and the footage so far looks PISH !

I'm generally pretty good with stuff like this but its really driving me nuts. Can I ask what routine you would follow to balance this thing? oh and what cam your using?

Last edited by Mat Thompson; March 22nd, 2009 at 05:26 AM.
Mat Thompson is offline   Reply With Quote
Old March 22nd, 2009, 01:04 AM   #10
Wrangler
 
Join Date: Jan 2002
Location: Los Angeles, CA
Posts: 6,781
Mat:

The basic balance routine involves adjusting the camera platform side to side, front to back and top to bottom (bottom heaviness). Roughing in bottom heaviness first, proceed to rough in side to side and front to back. You will find that once you "fix" one axis, the next one that is the most obviously off kilter will manifest itself (i.e. if very front heavy, once you dial the camera back it may start to fall to one side, so fix that next).

Once you have static balance and you achieve a 2-3 second drop time, you can begin to work with your rig.

Understand that a rig will almost always "pendulum" or sway when you accelerate or decelerate. The video you posted must have had a fairly long drop time as little of this is apparent. A long drop time is tough to work with especially for beginners.

The true skill of operating a stabilizer is learning how to "contain" the forces of acceleration which is done with the hand on the post below the gimbal. That light fingertip touch that is required to aim the camera also is responsible for gently counter-acting the forces that are manifested on the rig during accelerations. It takes a lot of practice to achieve this--the rig does NOT do it for you. Expect to see plenty of sway and roll in your early efforts.

By the way--you ARE operating with both hands, yes?!
__________________
Charles Papert
www.charlespapert.com
Charles Papert is offline   Reply With Quote
Old March 22nd, 2009, 09:15 AM   #11
Major Player
 
Join Date: May 2008
Location: Bedfordshire, UK
Posts: 863
I use an FX1 with high capacity battery and on my gc2000 i use all the weights so the post stays short (long post=more tilt inertia, which isnt normally good).

to balance i get my drop time roughly right, then do my side to side, front to back balance and fine tune my drop. fine tuning the static balance is then done by shifting the weights around.

the heavier the entire rig, the more stable it will beb but for this reason i got the vest as hand held killed me.

asyou adjust the weights and post you will find your balance will shift, just keep tweaking till its done. you may want a quick release as this gets boring after a while. its also worth a mention that the glidecam gimble is a little poo as you can balance it nicely then turn 90 degrees and its all out again.
Danny O'Neill is offline   Reply With Quote
Old March 22nd, 2009, 12:32 PM   #12
Regular Crew
 
Join Date: Mar 2008
Location: Los Angeles, CA
Posts: 83
It took me forever to get mine balanced... I've only used it a couple times because its such a pain in the... gimbal.
Tom Sherwood is offline   Reply With Quote
Old March 22nd, 2009, 12:51 PM   #13
Wrangler
 
Join Date: Jan 2002
Location: Los Angeles, CA
Posts: 6,781
Good point about length of post, Danny. Shorter is always better in terms of overall operation (it helps equalize the feel between axes) but with a handheld stabilizer and a heavier camera, a longer post means less weight on the bottom which can make the rig less fatiguing to operate. Worth experimenting to find a happy medium.

And yes, the Glidecam gimbals are not that great when it comes to linearity.
__________________
Charles Papert
www.charlespapert.com
Charles Papert is offline   Reply With Quote
Old March 22nd, 2009, 04:20 PM   #14
Trustee
 
Join Date: Sep 2006
Location: Kent UK
Posts: 1,397
Hi guys. OK today I've had a little more success. Charles thanks for your words, and I can see this thing isn't a plug and play solution for sure. I have got it balanced today, not perfect but enough to go out into a bit of local woodland and try it out.

I am going to capture some of the results shortly and I'll throw it up in this thread.

It is certainly hard on the wrist and I think a wrist brace would certainly help. I can also see that to use this for any length of time needs the vest/arm. Not only that though I did feel, 50% of my concentration was going into holding the thing up which of course means less on getting the shot right.

Anyway, for now thanks for all the help guys and I'll post some footage shortly....unless its terrible ;-) !
Mat Thompson is offline   Reply With Quote
Old March 22nd, 2009, 04:26 PM   #15
New Boot
 
Join Date: Apr 2008
Location: Italy
Posts: 18
Hi Mat,
I am glad you have improved your rig set up. Now it is time to fly. I am sure you'll have great satisfactions with your rig.
Best,
Amedeo
__________________
Amedeo Fabroni
www.ciakframe.com
Amedeo Fabroni is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > Support Your Local Camera > Stabilizers (Steadicam etc.)

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 02:55 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network