Sound Card Shutter Tester

[kev curry]

I fancy trying to put one of these together but can I rely on the accuracy of one of these home made devises? Any experiences?

muchas gracias

http://www.davidrichert.com/sound_ca...ter_tester.htm

[aduncanson]

The rise and fall times of the phototransistor are 3 millionth's of 1 second.
The sound card and Audacity samples the signal 44,000 times per second by default.

These figures should allow you to time a 1/500th second shutter speed to reasonable accuracy, say to within about 1/60th of a stop.

Is that good enough for your color transparencies?

[Greg Lockrey]

They're accurate enough for photographic purposes.

[kev curry]

Smashing guys thanks.

Now to get the bits a bobs and start soldering. Me no need no stinking overpriced Calumet tester

[Ron Marshall]

Instead of building an optical set-up, would it be possible to use a microphone with the same software.

I assume since this is simpler and not being done that there must be a downside?

I only need to test speeds from 1 to 1/30.

[aduncanson]

Instead of building an optical set-up, would it be possible to use a microphone with the same software.

I assume since this is simpler and not being done that there must be a downside?

I only need to test speeds from 1 to 1/30.

I had read somebody suggest this and tried it once with the very loud shutter of my Fuji GW690III. I may not have persevered sufficiently and my microphone was the worst possible, but I was never able to differentiate the opening and closing of the shutter. I am not sure that I was using Audacity at the time either.

I would suggest that you give it a shot. It sure doesn't cost a lot to try.

[Ron Marshall]

I would suggest that you give it a shot. It sure doesn't cost a lot to try.

Unfortunately it entails a probably extensive search for the microphone that came with the computer, which in any case is not good quality. Probably cheaper for me to make the optical tester than to purchase a good mic. Thanks for the info.

[C. D. Keth]

I wouldn't go with the microphone. How do you know what part of the noise of the shutter actually coincides with the opening and which part goes with the closing? If you record a shutter well, you will hear much more than 2 clicks.

[Bill_4606]

I've used the Audacity program with a very cheap microphone and found it more than adequate for shutter measurements longer than 1/250 sec. I also have a photo transistor apparatus similar to the one in the project diagram referred to in the original post. Instead of connecting to audacity, I connected it to a very high speed digital storage scope. I found the slew rate (speed) of the photo transistor to be a problem at speeds faster than 1/500 sec -- but still usable.

Back to the Microphone... for shutter speeds longer than 1/125 I would definitely use the microphone. I even used it with my di$%al SLR camera and could see in the Audacity wave form where the mirror raised, shutter clicked (start and stop), and mirror returned. The lesson here is that you get a little more information with the microphone than the light sensor.
Regards,
Bill Riley

[Ron Marshall]

I've used the Audacity program with a very cheap microphone and found it more than adequate for shutter measurements longer than 1/250 sec. I also have a photo transistor apparatus similar to the one in the project diagram referred to in the original post. Instead of connecting to audacity, I connected it to a very high speed digital storage scope. I found the slew rate (speed) of the photo transistor to be a problem at speeds faster than 1/500 sec -- but still usable.

Back to the Microphone... for shutter speeds longer than 1/125 I would definitely use the microphone. I even used it with my di$%al SLR camera and could see in the Audacity wave form where the mirror raised, shutter clicked (start and stop), and mirror returned. The lesson here is that you get a little more information with the microphone than the light sensor.
Regards,
Bill Riley

Thanks Bill. I will dig out my mic and give it a shot.