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Old 12th May 2019, 06:05 PM
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Default Tripod stability hanging weight

https://thecentercolumn.com/2018/02/...nd-damping-vs/
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Old 12th May 2019, 06:28 PM
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Thanks for posting, interesting test results that make sense to this engineer, albeit will surprise many people.

Has to be said though that I agree with one of the comments on the article, main purpose is to stop your rig blowing or getting knocked over by wind.
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Old 12th May 2019, 06:41 PM
Alan Clark Alan Clark is offline
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I once made a Benbo-type tripod out of quite large diameter aluminium tubing, to use with a home-made 5x4 camera. It didn't seem ultra-stable, so I balanced a sherry glass filled with water on top of the front standard, to check for vibrations. When I fired the shutter, water rippled in the glass. Not good. So I tied a 7lb bag of potatoes to the tripod, and repeated the test. the water still rippled.

I concluded that adding the weight to the tripod made no difference because the tripod itself was made from what guitar makers call a low damping material. Just rapping the tripod leg with a knuckle would set the whole thing off vibrating. What is needed to stop vibrations is a high damping material. Carbon-fibre fits the bill here. So does wood, though some woods are higher damping than others. With my carbon-fibre tripod, a simple but fairly hefty ball and socket head, and a home-made wooden 5x4 camera made from high-damping wood, I can apply the sherry glass test and get no water ripple at all when the shutter is fired.

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Old 12th May 2019, 07:10 PM
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Quote:
Originally Posted by Alan Clark View Post
I once made a Benbo-type tripod out of quite large diameter aluminium tubing, to use with a home-made 5x4 camera. It didn't seem ultra-stable, so I balanced a sherry glass filled with water on top of the front standard, to check for vibrations. When I fired the shutter, water rippled in the glass. Not good. So I tied a 7lb bag of potatoes to the tripod, and repeated the test. the water still rippled.

I concluded that adding the weight to the tripod made no difference because the tripod itself was made from what guitar makers call a low damping material. Just rapping the tripod leg with a knuckle would set the whole thing off vibrating. What is needed to stop vibrations is a high damping material. Carbon-fibre fits the bill here. So does wood, though some woods are higher damping than others. With my carbon-fibre tripod, a simple but fairly hefty ball and socket head, and a home-made wooden 5x4 camera made from high-damping wood, I can apply the sherry glass test and get no water ripple at all when the shutter is fired.

Alan
Alan I applaud your testing technique may I suggest a single malt in the glass instead of water, you can then celebrate or drown your sorrows with a wee dram.
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Old 12th May 2019, 09:06 PM
Alan Clark Alan Clark is offline
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Norm, I think your idea to use whisky instead of water is an excellent one.

If you send me a bottle, I will definitely give it a try....

Alan
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Old 13th May 2019, 11:31 AM
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Quote:
Originally Posted by Alan Clark View Post
Norm, I think your idea to use whisky instead of water is an excellent one.

If you send me a bottle, I will definitely give it a try....

Alan
Sorry Alan, tried the stability test; after several experiments the whiskey is all gone and I am definitely un-stable and my results are inconclusive. Maybe water is the way to go
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Old 13th May 2019, 12:08 PM
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Norm, in the name of scientific integrity you simply must carry on as you were. Changes in any one variable will only lead to more confusion. Whiskey it was, so whiskey it must be.
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Old 13th May 2019, 02:25 PM
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Having read and reread the article I still can't work out whether the centre column was fully extended or not. I always prefer to have the centre column as low as possible and use the tripod legs to get the height.
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Old 13th May 2019, 03:26 PM
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That tripod testing website is a strange one. The guy mentions not long after he started it that he would show how all the various tests he conducted related to image sharpness in real life. And then he didn’t do it - at least I couldn’t find another post about it.

So there’s all this information about torsional rigidity, oscillations, stability, damping, etc, with tripods rated against each other but no proof that any of it matters from a practical viewpoint. Do the measurable differences in testing make any difference to the sharpness of a print?

If there are little to no demonstrable real-life differences between tripods then it’s all just geekery as far as I can see. Unless I just missed the post that tied it all together.


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Old 13th May 2019, 05:48 PM
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I wonder if the old masters used to think about all this ? Or did they spend their time just making great images .............

Neil.
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