Archived posting to the Leica Users Group, 1998/08/04

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Subject: Re: [Leica] Checking a tripod for resonance
From: "Henning J. Wulff" <>
Date: Tue, 4 Aug 1998 16:27:05 -0700

Gary wrote:

>> Thanks Alan I needed someone else to say it before I did. Boy I'm glad
>> there is someone else who thinks all this "vibration stuff is <<<
>>              <<<" a little too anal>>>>
>> I guess somewhere in the world this is a required excercise, but for the
>> life of me I can't imagine when it matters diddly squat to someone using
>> Leica, RF or SLR.
>Actually, Ted, I wish I had done the water test last fall before taking my
>280/4.5 Telyt on an SL up to document a monastery near Kodiak, Alaska.
>Almost all of the daylight shots in shade where I was trying to get some
>dof turned out blurred from resonant camera shake on a tripod. Most of the
>shots were in the 1/4 to 1/30 second range.

The more accurate way to test for vibrations is to use a small mirror stuck
onto camera, lens or tripod head, point a small hand laser at it and have
the light bounce onto a flat surface. The further the travel distance from
mirror to wall, the more sensitive the test will be. Fire the shutter, and
watch the light dance. The reason this works better is twofold; if the
mirror to wall distance is long enough, the test will show vibrations that
you would never see with the water glass. Also, a small mirror has much
less inertia than a glass of water, and will not likely have its own
resonant frequency that is close to the camera/lens/tripod system.

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