Concept for a Shutter Tester
Proposed Shutter Tester
I can't do this. I do not have the knowledge vbase in electronics or the skill set toi even experiment with this idea. Maybe someone here can.
I understand that folks have used a sound program to capture the actual sound of a shutter functioning and derive a shutter speed from that. The idea that popped into my thoughts was to use a light detector to generate a current that would be processed into a sound signal. As the light increased the "sound" signal would get stronger, then weaker based on the amount of light falling on the detector. The sound application would then display this as a curve and measure of the duration of the shutter's action would come from that.
Dunno what components would be needed or how to put them together. I have no idea what software would be needed either. In the home workshop version, this might be the size of a shoe box and require separate light. In the refined commercial version, the whole thing would fit onto the front of a lens like a lens cap and be the size of a soda can . . .with blue tooth connection to a smart phone for the display.
A quick check of the actual shutter speed could be made in the field with the soda-casn model.
Maybe the best approach is to build it as a focal plane detector instead of at the front element.
Too much late afternoon coffee on a rainy day I guess . . .sorry.
Re: Concept for a Shutter Tester
Re: Concept for a Shutter Tester
A light sensitive detector and an oscilloscope have long been the basis of some shutter testers. This lets one plot light against time for a more comprehensive test than testers that integrate the light during the exposure to yield a figure that simplifies exposure calculation. Simple additions to the circuit also check flash sync delay. For focal plane shutters, the light detector should be small, and near the plane of the shutter. In this case, several readings should be made along the direction of travel of the shutter. Detector position is less important when testing between-the-lens shutters. I consider shutter testers like these far more useful than those that rely on sound.
Re: Concept for a Shutter Tester
A bit of a different frequency on the scale of wavelength... :-)
Steve K
Re: Concept for a Shutter Tester
There's some diy schematics out there that do what you ask, except you need to hook it to a computer. Basically, you use an infrared detecting LED in series with a 9v battery, a resistor, and solder it to a minijack (mini headphone jack). Plug the jack into your laptop, start the free software program Audacity, hit record, and then whatever light hits the sensor makes a nice peak in the DC voltage at audio frequencies. I built one about two or three years ago. I can't point you to the tutorial that showed me how, but there's probably enough keywords in this post to do the trick.
Now, replacing the computer with something compact? An RasberryPi mini computer should do the trick, and there's at least one youtube video of it running Audacity. Someone cleverer than me could code something on the Pi that will automatically read the audio stream and spit out the duration of the square waves you get from the sensor. And, probably pipe the output to a simple set of 8-segment LEDs. Bluetooth would be harder.
My experience was the difficult part was interpreting the "sound wave" graph correctly. It took quite a few trials to get consistent results due to operator error. A fun project, though.
Re: Concept for a Shutter Tester
Will F.: Thanks for validating my early AM Brain-Burp. Glad to know that it is possible. Hope this plants a seed with someone with the ability to do make it happen.
Still hoping for the Soda-Can model.
Re: Concept for a Shutter Tester
Re: Concept for a Shutter Tester
Quote:
Originally Posted by
coisasdavida
I have used that app extensively with the adapter.
Works great.
I need to find it in my moving boxes....
Re: Concept for a Shutter Tester
Looks great! So it seems to work using the actual SOUND of the shutter operating?
Doesn't use the amount of light coming through the lens? And this is a DIY assemble at home project, too I gather. I don't think my phone has that plug-in though. Maybe there is a cross-over cord at Best Buy.
Looks pretty much like what I had in mind. Thanks for the info!
Re: Concept for a Shutter Tester
The problem I had with used sound-based shutter testing apps was you need to figure out where to put the points on the sound wave. It wasn't obvious all of the time I was never sure how accurate it was.
I bought a Phocron XA shutter tester when they launched on Kickstarter. It's really easy to use and gets repeatable results.