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-   -   Tripod Isolation from Ground Vibration (https://www.dvinfo.net/forum/tripod-sticks-heads/121828-tripod-isolation-ground-vibration.html)

Robert Bunker May 17th, 2008 08:58 AM

Tripod Isolation from Ground Vibration
 
I shoot train movements close to trackside and notice image "instability" when I'm taping near rough track. Obviously this is vibration passed to the camera through the tripod so I'm looking for some way to isolate the tripod from the ground while maintaining stability. Is using one of those "beanbags" under each leg a possibility or does someone manufacture a foam product for this purpose? Thanks for any guidance.

Jack Walker May 18th, 2008 12:19 PM

First, use a tripod made of wood. (Carbon fiber and basalt/fiber glass are better than metal.)

There are the Meade vibration isolation pads:
http://www.astronomics.com/main/prod...product_id/895

Read paragraph 2 of this article for some typical ways to dampen ground vibrations:
http://www.pietro.org/Astro_C5/Mods/tripod_tray.htm

Here are some ideas:
http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00BXbT

Dan Keaton May 18th, 2008 12:31 PM

It would be interesting to determine if the Meade Vibration Isolation pads help or not.

Depending on your tripod, I would first hang a heavy weight from the top of the tripod legs.

My Sachtler Speed Lock II legs have a hook for this purpose. This hook is also used to secure the tripod such as when working on a dolly.

Andy Tejral May 18th, 2008 01:12 PM

Having some experience here (www.vimeo.com/user390555/videos youtube.com/user/ynda777) I don't think there is a solution here. The forces involved are just too great. The best you could do is keep steadyshot on and correct any pans in post.

The Meade things are designed for minimizing small vibrations--not the rather huge excursions you're talking about. I'd love to be proven wrong of course.

Hanging a weight is only going to increase the 'coupling' which is exactly what you don't want.

Travis Cossel May 18th, 2008 08:48 PM

I wonder if a couple of those yoga mats would do the trick, or something similar. The material is kind of like rubber, so it should reduce the vibrations. I agree that hanging weight isn't going to help, but rather hurt the situation since you're dealing with some nasty vibration.

You might consider using a stabilizer instead of a tripod for the shots, that way your body would eat up all of the vibration.

Jack Walker May 18th, 2008 10:10 PM

How about setting up in the back of a pickup or the top/hood of a car. The tires should absord most of the vibration?

I don't know if this idea would work, but it would be easy to test.

Giroud Francois May 19th, 2008 01:00 AM

you can build a platfom with two plywood plate and some tennis ball sandwiched in between.

Peter Ralph May 19th, 2008 03:38 PM

Andy - can you explain your "coupling" comment?

Andy Tejral May 19th, 2008 05:39 PM

Quote:

Originally Posted by Peter Ralph (Post 880128)
Andy - can you explain your "coupling" comment?

I'm not sure but here goes: The more weight you have on the tripod, the more the tripod is going to 'be one with' the ground. The force pulling down firmly connects the tripod to the ground. A lighter tripod is easier to tip over, less connected to the ground.

If you are trying to eliminate wind vibration, that is good--generally the ground doesn't move unless you're in earthquake country, which is essentially what we're talking about here--mini, repetitive earthquakes.. The force of the train literally moves the ground so you want the tripod 'to be separate from' the ground.

Did that help?

Allen Plowman May 19th, 2008 05:46 PM

Quote:

Originally Posted by Andy Tejral (Post 880175)
I'm not sure but here goes: The more weight you have on the tripod, the more the tripod is going to 'be one with' the ground. The force pulling down firmly connects the tripod to the ground. A lighter tripod is easier to tip over, less connected to the ground.

If you are trying to eliminate wind vibration, that is good--generally the ground doesn't move unless you're in earthquake country, which is essentially what we're talking about here--mini, repetitive earthquakes.. The force of the train literally moves the ground so you want the tripod 'to be separate from' the ground.

but if the tripod is stable, and separate from the ground, wouldn't that show the ground shaking, still perceived as movement? if the tripod is secure to the ground, it would move with the earth, and appear as a stable picture, right?
wrong?
maybe?

Andy Tejral May 19th, 2008 05:55 PM

Quote:

Originally Posted by Allen Plowman (Post 880177)
but if the tripod is stable, and separate from the ground, wouldn't that show the ground shaking, still perceived as movement? if the tripod is secure to the ground, it would move with the earth, and appear as a stable picture, right?
wrong?
maybe?

I was trying to be generic in my response but perhaps being more specific is better here.

Picture a train, specifically a North American freight train. Each car has a 'truck' at either end so the weight of two cars is clustered together. I guess, if you shot the nearest part of the train, yes, the motion of the ground would be very close to the motion of the train.

But generally, you want a variety of shots, no? Say a long shot down the length of the train. Worse, make it a telephoto shot--more susceptable to vibration. The movement of the train is an inch or two and will not be apparent once you get 100' or so from your location. But move the lens that much and you'll notice a definate jiggle in the image.

Peter Ralph May 19th, 2008 07:34 PM

I see what you mean - but is that a valid analogy? Vibration will often cause secondary movement, which, in lighter objects amplifies the movement. In this case surely a heavier tripod would be more stable. Being securely coupled to the ground is better than bouncing around on top of it.

Robert Bunker May 21st, 2008 10:48 AM

Tripod Isolation from Ground Vibration
 
Thanks for all the ideas. I going to investigate those Meade Anti-Vibration Pads. Turns out B&H has them in their Summer 2008 catalog on P. 458 in the Optics section.

Thanks again for the ideas.

Alex Williams May 21st, 2008 06:53 PM

Please let us know what you think of the pads.


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