so i have read the white paper by Dr. Kim and have seen various web pages talk about this - the notion that CF reduces vibration. i think i get the physics. what is not clear to me is, what vibration factors does CF really reduce? wind induced? lets say mirror slap is eliminated via MuP, of course there is some shutter induced vibration - but since you are connected to the tripod via a metal head - how can the CF have any impact on that?
As my school training was in structural engineering, this is an easy one to answer. Any material used to make a tripod that works needs to be viscoelastic.
A perfectly elastic material snaps back immediately - think of a billiard ball as being pretty close to being perfectly elastic. When it's struck by another pool ball, it deforms and snaps back immediately in the energy transfer. The opposite of elasticity is plasticity, by the way, in where if two perfectly plastic billiard balls struck each other they would deform and never snap back into shape and more or less fuse together.
Viscoelastic materials add viscosity to the mix, in that they act like a viscous liquid when stress is applied, and when it's applied in a cyclic fashion (vibration) this viscosity causes the waves to become out of phase and start to cancel each other out.
Aluminum is far more elastic than carbon fiber and dampens vibrations less at all frequencies. This is also part of what makes the 787 Dreamliner so quiet (the other part of course being that it's not flying at all at the moment). Although wooden tripods can also be very viscous, the nature of wood being a grown rather than manufactured product leads to wide inconsistencies, and of course it weighs quite a bit more in virtually all cases. A theoretical cellulose resin tripod, which could be manufactured and act somewhat like wood, is more elastic than carbon fiber.
thanks, at first i didn't think much of this..but yesterday i had my d200 on my bogen 3011 with 329 head and 300mm..using MuP mode..i triggered the shutter while placing hand on the tripod about midway up...i was quite surprised how much vibration was felt...
after that i sumarily went to B&H and went Carbon....
The potential sources of vibration are numerous. Vibration is a complex subject - waves, oscillation, harmonics, damping, vibrations from multiple sources as waves meeting each other in phase or out of phase. Different materials have different resistance to vibration and different damping effects.
Vibrations start and they have to go somewhere - air, ground, a person holding the tripod, heat, etc. Depending on the equipment and support, vibrations can take a surprisingly long time to dissipate - even mirror slap vibrations when you're using MUP on an under-spec'ed tripod.
I think the simple answer is that in tests and in use, CF has demonstrated a superior weight to performance capability to control vibrations. The weight word is important. You can make tripods out of aluminum or wood that can have an equivalent damping effect to any CF tripod - they'll just have more mass than most of us want to cart around.
>Hi Chris, > >I pulled the trigger on a Gitzo 2531...that and the Q10 should >complete my purchases for tripod gear for the next few >years.... > That's the exact same tripod and head I purchased a couple years back, and couldn't be happier.