Where is the center of gravity on an XL2? at DVinfo.net

Jason Varner · October 18th, 2005, 09:27 PM

I recently built a small crane for my xl2. It's a fairly simple model using pulleys and an underhung sled. I want to modify it so that I have tilt control. If I can figure out the center of gravity I can have a sled fabricated that will put the camera's centerline on that of the pulley's and keep the apparatus balanced which seems to be the key in any jib/crane contraption. If anyone out there knows where the magic spot is I'd appreciate the help. Thanks, Jason.

Greg Boston · October 18th, 2005, 09:34 PM

As you probably know, the stock XL2 is a bit nose heavy. Your best bet is to put some weight on the rear accessory bracket that will put the CG right at the tripod connector screw. This will simplify the design of the support sled.

-gb-

James Emory · October 19th, 2005, 01:06 AM

Another way to find CG is to simply place a pen under the base on a flat, level table and adjust the pen back and forth until it balances on the pen. That point will be the CG.

Vence Vida · November 4th, 2005, 03:37 PM

Jason,

I know it's been a couple of weeks since you posted, but I'm just stumbing across your question.

I built a crane a few months ago for use with my XL2. Like Greg said, I used extra weight on the rear - an ankle weight, like you use to exercise attached to the accessory bracket. I even use is when the camera is on my shoulder, because it helps to balance it in that situation as well.

The only problem with this, as you may have already discovered, is that one of the keys to a small home-made crane is the effect of even a few extra ounces out on the business end of the thing. It requires a great deal of extra counterweight at the rear to then balance the crane, and depending on how light you built it, the total weight can overwhelm the design very quickly. You are much better off finding the "sweet-spot" and rigging a way to place the center of gravity on your pivot point, rather than just adding weight to the rear of the camera. I learned from experience.

James Emory · November 7th, 2005, 01:38 AM

Jason, you really need to make a cut out and centered X (fore & aft, left & right) on the mounting plate where the bolt that attaches the camera plate will slide in for adjustment. This way you can slide the camera fore and aft to achieve the correct balance. That's how my jib's mounting plate is made and most others are as well.

October 18th, 2005, 09:27 PM	#1
Jason Varner Major Player Join Date: Aug 2005 Posts: 119	Where is the center of gravity on an XL2? I recently built a small crane for my xl2. It's a fairly simple model using pulleys and an underhung sled. I want to modify it so that I have tilt control. If I can figure out the center of gravity I can have a sled fabricated that will put the camera's centerline on that of the pulley's and keep the apparatus balanced which seems to be the key in any jib/crane contraption. If anyone out there knows where the magic spot is I'd appreciate the help. Thanks, Jason.

November 4th, 2005, 03:37 PM	#4
Vence Vida Major Player Join Date: Feb 2005 Location: Indianapolis, Indiana Posts: 218	Jason, I know it's been a couple of weeks since you posted, but I'm just stumbing across your question. I built a crane a few months ago for use with my XL2. Like Greg said, I used extra weight on the rear - an ankle weight, like you use to exercise attached to the accessory bracket. I even use is when the camera is on my shoulder, because it helps to balance it in that situation as well. The only problem with this, as you may have already discovered, is that one of the keys to a small home-made crane is the effect of even a few extra ounces out on the business end of the thing. It requires a great deal of extra counterweight at the rear to then balance the crane, and depending on how light you built it, the total weight can overwhelm the design very quickly. You are much better off finding the "sweet-spot" and rigging a way to place the center of gravity on your pivot point, rather than just adding weight to the rear of the camera. I learned from experience. __________________ Sony PMW-EX1R, Canon XL H1, XHG1, Panasonic GH2, Mac Pro 3.2 Quad running FCPS 3, FCPX, & Adobe Creative Cloud CC www.creativejuicesvideo.com

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October 18th, 2005, 09:34 PM	#2
Greg Boston Wrangler Join Date: Oct 2003 Location: DFW area, TX Posts: 6,117 Images: 1	As you probably know, the stock XL2 is a bit nose heavy. Your best bet is to put some weight on the rear accessory bracket that will put the CG right at the tripod connector screw. This will simplify the design of the support sled. -gb-

October 19th, 2005, 01:06 AM	#3
James Emory Regular Crew Join Date: Aug 2002 Location: Atlanta, Georgia Posts: 1,892	Another way to find CG is to simply place a pen under the base on a flat, level table and adjust the pen back and forth until it balances on the pen. That point will be the CG.

November 7th, 2005, 01:38 AM	#5
James Emory Regular Crew Join Date: Aug 2002 Location: Atlanta, Georgia Posts: 1,892	Jason, you really need to make a cut out and centered X (fore & aft, left & right) on the mounting plate where the bolt that attaches the camera plate will slide in for adjustment. This way you can slide the camera fore and aft to achieve the correct balance. That's how my jib's mounting plate is made and most others are as well.