Dave,
If it hasn't already been suggested, you might try using an LED. They
generate a small voltage when light hits them, and I'd bet they have a way
faster response to light than the photocell.
hope that helps,
patbob ([EMAIL PROTECTED] [EMAIL PROTECTED])
> Date: Tue, 29 May 2001 19:29:22 +1200
> From: "David A. Mann" <[EMAIL PROTECTED]>
> Subject: Re: Shutter speed testing
>
> Rob Studdert writes:
>
> > What equipment/set up was used to perform the shutter speed tests?
>
> I was saving that for the web page :)
>
> Basically all I did was shine a low-power laser into the
> shutter, with a small
> silicon photocell on the other side, so the photocell gets
> lit up while the shutter
> is open.
>
> Attached to the photocell was a digital oscilloscope in
> single-shot mode,
> triggering off the rising edge. The 'scope has an automatic
> pulse-width
> measurement so I just used that to measure how long the
> shutter was open.
> The 10mW laser gave me about 400mV (or 0.4V for the
> non-metric) out of the
> photocell so I had plenty of signal to work with.
>
> It worked well until the really high shutter speeds (above
> 1/1000 on the Z-1p)
> where a combination of the speed of the silicon cell and the
> width of the slit
> relative to the beam caused inaccuracies. That's my theory, anyway.
>
> All the rest of the work (converting all the info into "X
> stops over/under") was
> done using a spreadsheet.
>
-
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