I would like to share an adapted (??) technique for testing shutter speed.

I found a link (http://www.davidrichert.com/sound_card_shutter_tester.htm)
which demonstrates using a phototransister and your computer's sound card. I built the contraption and it works, but not very well beyond 1/60 of a second (at least for me). I used a photodiode as well; same poor results at high speed.

The adaption was to hook the wires to the lens bi-pole synchronizer instead of the photoresister (not needed at all now). So if the shutters (and synchronizer) are working correctly they should close the circuit when the shutter is completely open and break it as it closes.

This worked great at all speeds, and since I had already collected data with the photoresister I can tell you it is also accurate. The big benefit is that I can test the faster speeds as well.

After carefully Ronsonol washing the shutter and gears, everything works consistently now. All speeds are 1/4 to 1/3 stop slow. the top two speeds (1/200 and 1/400) both fire at 0.003 milliseconds. I wonder if those two work off of a separate mechanism?

Big thank you to all who have posted here. Your advise has been invaluable.

novi wrote:

So if the shutters (and synchronizer) are working correctly they should close the circuit when the shutter is completely open and break it as it closes.

You know it, but for other readers of this post, I have to point out that the above is true only on X sync shutters or on fully sync'd shutters when the timer is at X or 0

Quote:

the top two speeds (1/200 and 1/400) both fire at 0.003 milliseconds. I wonder if those two work off of a separate mechanism?

I'm guessing you mean 3 milliseconds, 'cause .003 milliseconds is darn fast. Yes they do have their separate mechanism from the lower speeds and the 400 adds an extra spring.

Big thank you to all who have posted here. Your advise has been invaluable.[/quote]

Yes, that is 3 milliseconds. Thank you.

When you trip it sounds like 0.003 milliseconds though