Photocell responce time.
 

I want to use a photocell and a 200MHz fluke scope to measure the number
and duration of flashes made by a digital camera. For those of you who
don't know much about digital cameras and flashes, because of the way
digital cameras have to meter light from a flash, the flash fires
several very fast very short bursts before the "real" flash. I want to
know how many, how often and how long these flashes are. What I'm not
sure is if a photocell responds fast enough and where I can find spec
sheets and a source for one that is fast enough. I'm not sure on the
length duration I need to measure but I suspect the pre flashes will
last less than 1/40,000 of a second. I'm getting that number from
something I read a while back that said 1/40,000 of a second was the
shortest exposure time you could get from a flash to stop fast moving
action. That was several years ago though so I don't know what is
possible today.

--
Chris W

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Instead of using the CdS cell, why not use a silicon photo diode as the
receiver, I should think their response time would be pretty quick.

Paul