Greetings gentlemen, I have a few classic SLR cameras that I'd like to bring out of retirement. I need to establish if the shutter speeds are still within spec (or not as is more likely after 35+ years). I've already thought about how I might do this: open up the camera backs and place a super- bright LED up against the shutter curtain with a light-sensitive device on the other side of the shutter. Fire the shutter and view the response time (0.004s upwards) on a storage scope. What device would be fast enough to react to the momentary flash of the LED during the instant the shutter is open? Thanks.

Any reasonably small and fast photodiode. But you have to wire it into a circuit called "transimpedance amplifier" or TIA. Give it a good reverse bias but no more than abs max from the datasheet, that reduces its capacitance. You might also want to consider doing this in the IR range with filter in front of the photodiode (from an old TV set maybe) so daylight doesn't bother your measurement. The guru in that domain is Phil Hobbs who participates in this NG and has a web site with lots of good information, and he wrote a book about it: -- Regards, Joerg

What part would do this? (optoelectronics)

Apr 19, 2015 43 Replies

Rate this thread:

Cursitor Doom 11 years ago

That's what I do. B&W negatives are easy, simple and cheap to develop with just a few common chemicals and a developing tank. Total cost < 20 notes. Then it's scanner ------> computer.

Vote

Joerg 11 years ago

Yup! 30 minutes ago I took documentation photos of a prototype I built. Olympus PEN with Fotodiox adapter, using a Tokina EL 28mm and a Minolta MD Zoom 28-70mm. I bought the Olympus sans lens so I never used any of its automatic stuff.

Regards, Joerg http://www.analogconsultants.com/

Vote

Joerg 11 years ago

Like this?

formatting link

Such activity can teach a person more about RF and analog than a university. It did for me.

When I built other stuff such as early video games or big audio amps the fun was gone the millisecond it worked and I gave it away. Playing was boring. But when ham radio projects got finished I always used the heck out of the units for many years.

Regards, Joerg http://www.analogconsultants.com/

Vote

Cursitor Doom 11 years ago

I didn't like it; I *loved* it!

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required