the photoplug

The optical shutter speed tester for your smartphone.

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What is the Photoplug?

The PhotoPlug is a small light sensitive sensor which plugs into the headphone-jack of your smartphone. Together with the Shutter-Speed App (available FREE on the iOS and Android AppStore) it transforms your smartphone into a optical shutter speed tester for analog cameras.

The Plug contains a small light-sensitive element which converts light into electrical signals. All you have to to is opening the back of your camera, place it with the lens towards a bright light source, and position the PhotoPlug behind it. When you release the shutter, the light travels through the camera shutter and hits the PhotoPlug. The PhotoPlug measures the duration of that light pulse - which is equivalent to the shutter speed of your camera.

 
 

compact

The PhotoPlug is only 2cm short and perfectly fits in every pocket. It doesn’t require any batteries, so you always have it on hand when you need it. This allows you to use it wherever you are, for example when buying a used camera on a flea market.

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easy to use

Once you have taken a measurement, the App will display the measured shutter speed of your camera. It will also calculate a deviation value in f-stops. Example in the picture: You selected 1/125sec on your camera. Your measurement tells you it is actually 1/80sec. This results in an overexposure of 2/3 f-stops!

 
 

Step by step procedure

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Connect

Go to the “Camera Manager” to add/remove cameras that you want to check.

Connect the PhotoPlug to the Smartphone and select “Take new Measurement”.

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Setup the measurement

Open/Remove the camera back.

Point the camera against a bright light source.

Position the PhotoPlug behind the camera shutter.

Press the aperture symbol (turns red) and release the camera shutter.

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Analyze the measurement

The App displays a waveform with two peaks.

Zoom into the signal (two finger pinch) to maximize the signal to the full screen width.

Select the target shutter (the speed you set on your camera) on the bottom left corner.

Use the two blue sliders to measure the distance between the two peaks. Measure from the start of the first to the start of the second peak.

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save the data

Select “Save Measurement” to save the measured shutter speed. You can select from a list of cameras, that you previously added in the “Camera Manager” (see step 1). You can override individual values by saving another measurement to the same camera and shutter speed.

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view the data

After you saved the data, you can view it in the Camera Manger.

The Correction value is given in thirds of an f-stop. “+1” tells you to open the aperture by 1/3 f-stops in order to get a correct exposure. On the other hand “-2” tells you to close the aperture by 2/3 f-stops.