Shutter-Speed-Tester for the iPhone


TPF Noob!
Jul 16, 2013
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Hello !

My name is Lukas, I'm an analog photographer and I wrote a small application for the iPhone, which allows you to test the shutter speeds of your cameras, to see if they are still correct:
View attachment 50063
There are two possibilities of using the App:
1. The app alone uses a acoustic measurement method to determine the shutter speed. You can record the shutter release sound, and the App displays the waveform of this sound:
View attachment 50064
You will see two peaks in the signal, indicating the opening and closing of the shutter. From the distance between those peaks, the App calculates the shutter speed.

2. You can use the optical Fototransistor-Plug which I invented specially for this App. It contains a phototransistor and allows you to measure the actual light passing through the camera instead of sound:
View attachment 50065

This makes the measurements much more accurate, and works very well even at higher speeds like 1/500s !
View attachment 50066

The App is available on the iTunes AppStore: Link

If you want to try out the photoplug, you can buy it here: Shutter Speed Tester for Your iPhone Verschlusszeitentester FÜR Das iPhone | eBay

It would be great if some people here would try this out, as it was quite hard work to get this project to this point :)

Thank you,
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Sound-based shutter testers won't work on cameras having a focal plane shutter such as on most 35mm SLRs. At any shutter speed above the camera's flash synch speed the shutter operates with a "slit" of varying width that moves across the film plane and the sounds the shutter makes are not in direct relation to the exposure it provides for the film because it is the width and speed of the moving "slit" that determines this. Such cameras also produce sounds caused by mirror movements which occur before and after the actual exposure.

The same problem of sounds caused by mirror or light baffle movements also occurs on leaf shuttered SLRs.

Such a tester may work OK at slow shutter speeds but it is the faster speeds that are usually the ones that need testing the most.
sorry for my late answer. You are right, with focal-plane-shutters the acoustic measurement only works up to the flash sync speed of the camera. Above that speed, the time is regulated with the distance of the two curtains, which can't be detected in an acoustic signal (I also mention this in the App description btw).
Nevertheless, the measurement with the optical phototransistor-plug works perfectly well even with focal-plane-shutters, at least up to 1/500s. Faster speeds would require a sensor with two phototransistors, in order to measure the speed of the two curtains separately.
assuming, of course, the back of the camera can be opened.

mine can but it requires a hammer and chisel.
Well, measuring the shutter speed of a Camera without opening the back is Hard to do with any Method ;)

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