vibration in light tripods

[Brian Luce]

I have GH2's which weigh one pound. So I can use light weight tripods. I'm wondering though, when using hi power tele lenses that are prone to show vibration, if ANY light weight tripod is viable. I'm not an engineer, but it seems you need mass to absorb those tiny, shot destroying vibrations that are apparent with tele lenses. Smooth pans and tilts are one thing, but how about vibration? Even if you're willing to go Sachtler, can you get away with light sticks?

[Chris Soucy]

Originally Posted by Brian Luce

So I can use light weight tripods.

Well, you can, but don't expect rigid.

I'm wondering though.....................if ANY light weight tripod is viable.

That's one of those "how long is a piece of string" type questions. How high is your pain threshold?

but it seems you need mass to absorb those tiny, shot destroying vibrations

Well, yes and no. The art of tripod design and construction is to produce the most rigid support possible for a given weight, there always being a trade off in that equation, which is why five tripods from 5 manufacturers, all weighing the same, will have 5 different levels of rigidity.

can you get away with light sticks?

Another "string" question. For SD, probably, but what is your definition of "light"?

Here's an interesting and very informative table I've drawn up which pretty well sums the situation up.

These are sticks and spreaders only, no head. Rigidity increases in huge steps as you go down the list.

Sachtler SpeedLock 75 CF, 2:1:1, 2.6 kg

Libec RT - 30 B, AL, 2:2:1, 2.925 kg

Manfrotto 546B, AL, 2:2:1, 3.25 kg

Vinten Pozi - Loc 3819 - 3, AL, 2:2:1, 3.75 kg

Vinten FiberTec, CF, Nested I Beams, 4.65 kg

The difference in rigidity between the first and last is truly staggering, but so is the weight gain.

These rankings are not done on a "well, it doesn't feel very rigid" basis, they are based on actual measured and documented stress tests giving tripod deflection for a series of measured and repeatable rotational unit load stresses.

The first in the list I would not be happy shooting HD from, though people do and swear by them, pain threshold to the fore.

So, have I answered your question?


CS

[Brian Luce]

Okay, so weight and rigidity seem to have a 1:1 relationship according to your chart. And I can fully understand how and why some would be satisfied with the Sachtler speedlock, they might only be using short glass. Long glass brings in the vibration issues. About vibration, does rigidity directly correlate to it?

[Chris Soucy]

Yep, too right it does.

Imagine bolting a "top hat" http://www.bhphotovideo.com/c/product/578796-REG/Alan_Gordon_Enterprises_1004_HIHAT_100_1004_HIHAT_100_Hi_Hat_Support.html to a block of reinforced concrete a yard cubed.

Can't get more rigid than that.

If somethings vibrating with your cam mounted on such a fixture, it isn't the fixture unless you're experiencing an earthquake.

Which brings us to "head flex". Even if the mount is as described above, between the head/ mount interface and the camera itself there is always going to be a certain amount of flex, which varies due to manufacturing tolerances/ design/ material choice and once again, sheer mass.

A reputable head will show very little, but this is, again, a moveable feast, as with a 2000 mm tele on a HD camera "a little" can look like "a lot".

Then we have the curse of camera mounts the planet over. I refer, of course, to that throwback to the American Civil War, the single 1/4" - 20 S&W, 20 cent screw holding you're fantastically expensive HD camcorder with said 2000 mm lens to your equally expensive head and tripod.

How and why this appaling piece of Victorian era engineering has managed to escape the knackers yard of history has me totally mystefied and more than a trifle angry, as it shows, with a side to side wobble that simply cannot be avoided with such an arcane fixing.

All of which is down the track for you.

If you're using long glass, get a decent tripod, no way around it, lightweight simply cannot and will not do it at this point in time.

There is no such thing as a "light" (sub 4 kilo) tripod that can adequately handle long glass on a HD video camera system, untill we get to the next stage of camera support systems, which will work on a totally different priciple to those being produced now (IMHO).

When they are going to show I have no idea, but I keep prodding.


CS