Archived posting to the Leica Users Group, 1998/08/05

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Subject: Re: [Leica] Checking a tripod for resonance
From: "Henning J. Wulff" <henningw@archiphoto.com>
Date: Wed, 5 Aug 1998 11:55:59 -0700

GH wrote:

>I'll try this in the next few weeks, when I get some time.  It is extremely
>sensitive.  An x degree movement of the mirror causes a 2x amplification of
>the reflected beam.  With a long "throw" to the wall, extremely small
>deflections can be measured, and unlike the water, there is less dampening.
> In the past I have used a laser like this to demonstrate the amount of
>bending that happens in a table when a book is placed on it!  The laser I
>use is currently off being repaired.  It had a standard 1/4" tripod socket
>which will enable me to set it up on a second tripod and do this test very
>accurately.
>   One thing to be careful about, depending on the type of laser being
>used, ... make sure you don't look directly into the beam from the laser.
>It could cause serious eye damage.
>

I just use a $20 laser pointer that I bought for slide shows and prop it up
on a table. Even with this cheap laser the caution about not looking at it
is warranted. The whole setup takes just minutes and aside from the laser a
1" square mirror I have and some double sided tape. This provides all the
sensitivity I can use.


   *            Henning J. Wulff
  /|\      Wulff Photography & Design
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