Measurement of short shutter times

This may not be of interest to most photopaper pinholers due to the use of
'slow' paper relative to film, but I am wondering if it has crossed anyone
else's path...

After installing a pinhole on my 35mm camera, determining it's 'new' f-stop
(about 158) and taking some lightmeter measurements with my 'regular'
camera, I am realizing that with 100-200 ISO film and sunny days, I'm only
really looking at fractions of a second for exposure times...not in need of
reciprocity correction, and too short to manually operate the shutter with
any kind of accuracy...It's easy to do 10 seconds or 2 minutes
precisely...but 1/4 second isn't.

Since I 'converted' an old SLR, I'm tempted to use the existing shutter, but
the whole reason I chose that camera was because it's shutter was slow.

So, I am scheming over an idea (other side of my brain) for an electronic
circuit to allow me to measure the duration of the shutter opening...I have
an idea, but if anyone has run across something similar on the 'net
somewhere and is willing to refer me, I'd appreciate it.

If not, I'll share my idea in case it has any use for other people, assuming
it works.

I CAN see thru the SLR viewfinder/prism a bit...not very well, but maybe
better than just guessing.

Thanks

Murray
Received on Tue Jul 24 17:22:11 2001