Here is a Turntable that connects to your computer via USB, for the intention of digitizing your LP/vinyl records: Grace USB Turntable
Stephen
--- On Fri, 1/28/11, Herschel Mair <herschel@xxxxxxxxxxxxxxxx> wrote:
Thanks guys
Some interesting advice... I really need to buy a turntable! Lots of uses in product photography, QTVR etc. plus this... Alberto, I'll do the shots and send you the results to do the math/analysis :-) Actually I've mixed up your advice and I think what I'll do is shoot a falling black marble against a white background - continuous light at 1/3 stop intervals from 1/250 up to 1/8000. Then shoot it in the dark with the flash, and compare results...
The shutter is the most (Only) reliable timing device I have. I suspect that the useful duration at minimum power is between 1/1000 and 1/4000
Is there fault in my reasoning?.. tell me
Herschel
On 1/28/11 9:16 AM, ADavidhazy wrote:
> I think that what Alberto suggested re: CD player or such running at 7200 RPM just might work if its cover is black (paint it?) and put a white stripe along radius. It will be running at 120 RPS
or close to it (wow that seems real fast!) or about 4300 degrees per second so a 1/1000 second exposure time should leave an arc of about 43 degrees. But I suspect the flash will last longer than that and also that the output of the flash is not constant. It should show a fast rise time and then a longer decay time. Duration is typically expressed as time for 1/2 peak to 1/2 peak so it will be less than the total length of the arc ... you should see a tapering off of the light output along the blur.
>
> It is surprising how long flash durations really are when you give a more realistic estimate of this at 1/10 to 1/10 or so of peak output.
>
> Now what else might make a good measuring stick for this .... falling objects as he suggested also. Chris's suggestion is a bit extreme but interesting. A car going past you at 60 mph carrying the flash and firing it as it passes by a camera with open shutter? Hmmm got to think more
about this. ;)
>
> FWIW,
> Andy
>
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