Re: [Leica] RE: carbon fibre television tripod

[George Huczek <ghuczek@sk.sympatico.ca>]

At 10:32 PM 28/07/98 +0100, you wrote:
>Joseph Codispoti wrote:
>> Jeremy,
>> Thanks for the education on tripods. I have always held that the heavier
the
>> tripod the better the photo.
>
>Not necessarily. As Ansel Adams points out in _The Camera_, any tripod 
>will have a (set of) resonance characteristics (dependant on how it's set
>up), as will any camera/lens/shutter speed combination. These effects
>can interact in unfortunate ways. 
>
True.  Any vibration from the camera is transmitted through the tripod.  In
metals, these vibrations travel at roughly 1000 metres per second, give or
take a bit, reflecting from the free ends of the tripod and returning,
where they meet with other shock waves coming down the tripod.  This can
create sympathetic vibration, resulting in an increase in the amplitude of
the wave.  Even with fast shutter speeds there are enough of these
returning vibrations to create some problems. Working out the distance
travelled by the waves, even at high shutter speeds, the shutter is open
long enough for several of these reflecting waves to return in time to
cause the shakes.  
   Many factors are at play in determining whether the tripod will resonate
as a result of the vibration ... the length of the column, design of the
tripod, the type of materials used, thickness of the metal itself and the
width of the tubing, clamps, heads, connectors, etc.  
   I have a simple test which works well.  I got the idea from a column by
Stint (sp?).  He suggests balancing a glass of water on his Blads to check
for vibration on the tripod with and without using prerelease.
   This may work with rangefinder Leicas, but it is impractical with reflex
R's because there is not enough flat surface on the top to balance even a
small shot glass full of water.  Instead, I have found a small child's toy
which I can stick to the top of a pentaprism with some blue "sticky goop"
that is used to tack paper up on walls.
   The toy has a very light spring with a plastic head on top.  It costs
about a nickel (that's in US currency ... in Canada that nickel is now
worth about five bucks<g>).  When you "sticky goop" it to the dash of a
car, it discovered that it "goes crazy", shaking up, down and sideways with
the vibration.  You can make a similar device by taking the spring from the
inside of a ballpoint pen, attaching a light weight to the top, and
sticking the bottom of the spring on the hot shoe with blue sticky putty
(which will come off).
    With the camera on a tripod, you can visibly see if there is any
vibration.  The spring toy shakes noticeably with even the slightest amount
of vibration.  Experimenting with different shutter speeds, different
apertures, with and without mirror lockup, using mechanical self-timers,
etc. reveals any problems you might have.
    I tried this at a seminar where people brought in their cameras, cable
releases and tripods.  People also tried the test handheld to see how
steadily they could hold the camera.  This works nicely when looking into a
mirror.  
   One lady had a small (lightweight) aluminum tripod that was causing all
sorts of vibration problems.  It was worst when the tripod was fully
extended, at the height she normally used it because she had to extend it
fully when standing up.  After the camera was mounted on other tripods the
tests were repeated and we were able to conclude that it was her tripod
that was one of the main problems.  Try it. It is a quick and practical way
of seeing right away if your camera is vibrating on its tripod.
   A simple test like this is really useful.  I wonder how many people have
traded in lenses they thought lacked sharpness when they should instead
have traded in their tripods.  There are more used lenses than used tripods
on the market.  

- -GH