“Vibration resonance” – does your tripod suffer from the shakes?

[Heroique]

I’m curious if anyone has experienced tripod vibrations & blamed them on “vibration resonance” – and how you solved the problem.

I came across this curious term in AA’s The Camera – and I’m not so sure I’d be able to recognize the problem even if it was plaguing me.

“I have had many annoying experiences of this kind,” he says, “including one 19-pound tripod of great strength that nevertheless vibrated when used with a small 2¼ x 2¼ camera.”

So what exactly is vibration resonance? Apparently, it’s worse than just plain vibrations – it’s a sort of amplification of them. I’ll defer once more to AA:

“Vibrations that will reduce image quality may arise in an otherwise well-matched camera-tripod unit because of resonance. Every object has a resonant frequency, and if the wind or other force sets up vibrations at that frequency, they may persist for 10 seconds or longer.”

I’m no scientist, but I presume this means that if my tripod is stricken w/ the malady, its vibrations would last 10 seconds longer – or be more intense – than those of a similar tripod in similar conditions, but whose “resonance” is (by luck?) different.

If vibration resonance is a problem, AA recommends adding weight to the tripod, or wrapping its legs in heavy tape – and if the shakes persist, trying a different camera, or getting a different tripod!

AA says he’s had “many annoying experiences of this kind,” but has anyone here experienced it even once? How did you distinguish it from normal vibration? Can you share additional solutions?

[Ari]

On my list of things to worry about, photographically, I'd say vibration resonance would be at or near the bottom of the list.
For fun, you can see what vibration resonance did to a bridge in your part of the world back in 1940: http://www.youtube.com/watch?v=3mclp9QmCGs

[BetterSense]

Yes. A heavy tripod is no guarantee. Unfortunately, vibration avoidance is extremely complicated and hard to model. Experimentation is the only way.

[Heroique]

...[It’s] extremely complicated and hard to model...

At times, I’ve noticed my Ries/Tachihara vibrating in a slight wind, then strangely, stop vibrating when the wind picks-up! But it doesn’t always vibrate in a slight wind. I think the wind has to come from a certain angle, or the tripod has to stand at a certain angle, or a combination. Quite mysterious, this resonance…

[Brian C. Miller]

I use a Bogen 3036 tripod, and the extra bracing keeps the vibration at bay. A tripod like my two Benbos without bracing is suceptible to vibration. I have seen vibration on my small Benbo, but I think that it's mainly just because of the size. I haven't seen vibration on my large Benbo.

[Ash]

Considering most cameras are mounted on a single small screw, that's the issue. It you clamped the whole thing like a studio stand then locked it into the ground, you would be ok so long as nothing is vibrating in the ground.

[rdenney]

I've considered this at some length, and it's a subject that interests me for a lot of reasons and in many different applications (e.g. does the vibration of the brass in a tuba affect the sound? Answer: no. Does the vibration in a bicycle frame affect its perceived comfort? Answer: maybe.)

Here's an experiment: Place your favorite camera on a tripod in the normal position. Then, strike the tripod in various places with your fingernail. Listen for a ring.

When I was considering tripods many years ago, I had no access to a Ries, but I did compare a Bogen 3036/3047 combination to a much pricier Gitzo of similar heft. The Gitzo rang like a bell--"DING!". The Bogen..."THUD!" No ring whatsoever. Any audible frequencies were immediately damped. I bought the Bogen.

I will bet that a wooden tripod will produce a nice THUD.

That test only looks for audible frequencies of sufficient audio power to be audible. My suspicion is that the frequency range of vibration it might expose will be from something in the 100-Hz range to perhaps as high as 6000 or 8000 Hz. I would also suspect that any tripod will attenuate vibration at higher frequencies pretty well. But vibration at lower frequencies might still be a problem.

So, to check for that, I applied the laser test. I attached a laser pointer, with the button taped down, to the side of a medium-format camera's long 300mm lens, put the camera on the tripod, point the laser at the wall maybe 25 feet away, and then had my wife tap the camera while I studied the laser spot. There was very little ongoing vibration.

With a 500mm lens on a small-format camera, however, it was much worse. The large polar moment of inertia of a long lens means that once vibrating, it strongly fights to keep vibrating. Something with the weight more centrally located around the tripod axis minimizes the problem. And the larger the polar moment of inertia, the lower the resonant frequency. For really long lenses, the use of two tripods is the answer.

I'm not sure a single screw thread is a problem, unless the interface between the camera and tripod is either not rigid enough (which allows movement) or doesn't provide any useful damping. Generally, I would not expect the typical Arca-Swiss or Bogen hex-plate, when tightened appropriately to the camera, to allow much in the way of movement. The screw provides the clamping force, but it's the clamping force that does the work. The bigger the clamping area, the better. Rubber-covered plates might be a problem in some cases, but my experience with the cork-covered Bogen plates is that once they are properly tightened, they don't move. Arca plates generally don't have any resilient material, and often have a mechanical anti-twist connection to further prevent movement.

Rick "suspecting carbon composites do pretty well in terms of damping capabilities" Denney

[Brian C. Miller]

Another factor is how much vibration is generated by the camera itself. I have a Pentax 6x7, and the mirror and shutter on that beast will cause my little Benbo Trekker to swing like mad with a telephoto lens on it. Of course no such thing happens with my Bogen 3036.

But camera-generated vibration really isn't an issue when using a view camera and a shutter release. The little Benbo Trekker is fine as long as the ground is stable and the wind isn't blowing. It can handle 7 pounds of camera if I screw the camera directly to the tripod and I keep the center column at a minimum. (Of course this negates the benefit of a Benbo, but what the hey.)

[ic-racer]

If you bounce a laser off a filter on the front element and knock the tripod you can see the results of adding/subtracting mass or sandbags from your setup or adjusting leg height etc.

[Mark Sampson]

This seems to be a case of going looking for trouble; you can always find it if you look hard enough. Mr. Adams, obviously, was a fanatical detail-hound who spent most of his long career working with equipment inferior to the gear we have available today. I'm sure he found the limits of most of it, tripods included. There sure have been a large number of inadequate tripods made and sold, but most of us today can easily find something that will work without much effort.