Shutter-Speed-Tester for your iPhone
I'm a 19 year old student from germany and I wrote a small application for the iPhone wich might be interesting to some of you !
It is called "Shutter-Speed" and it allows you to measure the shutter speed of your camera by analyzing the shutter-release-sound.
After you recorded the shutter-release-sound, the app will display the waveform of this sound. Opening and Closing of the shutter produces two peaks, as you can see in the picture. From the distance between those peaks, the app calculates the shutter-speed and also tells you the deviation from the target value. Afterwards you can save your measurement.
More information here: http://www.echolot-online.de/Shutter-Speed.html
Best results can be obtained from cameras with diaphragm shutter (like TLRs). SLRs or cameras with focal-plane shutter do also work, but they produce a more complex waveform, wich makes it difficult to measure shorter times than 1/60.
I compared the results from this app with an optical measurement and the values are much more exact than you might think, at least for times longer than 1/500.
I would be very happy if some of you try out this app