>
> An interesting article regarding tripods was brought up in another group.
> http://www.berlebach.de/anleitungen/91.pdf
>
> also http://www.berlebach.de/anleitungen/52.pdf
>
> I can't help but wonder if "the stands extracted to one third of the
maximum
> length and loaded with 70% of their working load" wasn't chosen to give
the
> wooden tripods the best performance. Who carries a tripod that is tall
> enough to use at one third its length? I would think that the length would
> have a dramatic influence on resonant frequency (but hopefully your tripod
> isn't a musical instrument).
>
The tripod shown on the second page of the first document is an
impressive piece of hardware. I'm a bit surprised that the tripods with
solid cross-section legs would fare better than those with hollow metal
legs, as the hollow legs have more surface area (inside and outside) and
should dampen out vibrations more quickly. I wonder if the head assembly or
accessory shelf might be part of the problem.
When reading opinons on tripods in various nature photography books,
most authors did not desire leg braces as they made the tripod placement
difficult on uneven surfaces. From an engineering standpoint, leg braces
should reduce the vibration problem, at least at lower vibration
frequencies. I have a somewhat heavy Manfrotto 3001 which does not have
braces, as well as a much lighter Ambico V552 which does have braces.
Neither one has shown any noticable vibration problems.
But, both of these documents are discussing tripods for fairly heavy
astronomical telescopes where very long exposure times are an issue, so any
tendency towards virvration would be a problem for astrophotography.
Chris
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