Shutter-Speed

The App for measuring shutter speeds

    of analog cameras - just with your

      iPhone ! 

      Get the App and start making 

     precise exposures today !

       

As an analog Photographer you know the problem: Old cameras often lack in accuracy with their shutter speeds, wich can result in over- or underexposed images. But how can you determine, weather the 1/60 is still a 1/60 rather than a 1/40 ?

With this App, such measurements are easily possible.


How does this work ?

Every camera generates a shutter release sound. If you inspect the waveform of this sound, you will detect several peaks, produced by the various mechanical elements inside the camera.

By measuring the distance between those peaks, you can conclude to the actual shutter speed of your camera.


And this is exactly what this App does.

At first, you have to record the shutter release sound by tapping on the aperture symbol:

Tap again to stop the record. Please remind that recording time is limited to 3 seconds ! It takes a few seconds until all the data is processed. Once complete, a new view pops up:

This is where „the magic happens“: The shutter release sound you recorded previously is now shown as a waveform. Use the Two-Finger-Gesture to zoom in and out, until you see a signal similar to the one above.

Next, use the two blue knobs below the signal to measure the time between the two peaks.

With the button in the bottom left corner, you can set the Target shutterspeed. This is the shutter speed you set on your camera.

In the example above, the camera was set to 1/30sec. The measured time was 1/24,5sec. The deviation from the target value (1/30) is +1 third of a f-stop, this means the camera is overexposing the film by 1/3 stop !


Once you finished your measurement, you can either go back and make a new one or save it to a camera you created previously, by tapping on „Save Measurement“.

After you saved the measurement, you can go back and proceed with the next shutter speed.


You can create a new camera by tapping the „Edit“-button in the camera manager:

By tapping on one of your saved cameras, a table with three columns will appear:

The left column shows the target value. The column in the middle shows the actual value that you have measured. The right column now gives you a correction value you have to set on your camera in order to compensate for a wrong shutter speed !

Please pay attention: This numbers are thirds of a f-stop ! 3 is a full stop, 6 are two stops, and so on.

A negative value means that you have to decrease (close) your aperture, a positive value that you have to increase (open) it.



At Last, some recommendations for getting good results:

  1. •Best results are obtained from cameras having a diaphragm shutter (german: Zentralverschluss), as this cameras don‘t produce much ambient noise, like the mirror in an SLR

  2. •Always hold your iPhone as near as possible, with the homebutton facing towards the camera

  3. •If possible, perform the measurement in a quiet environment

  4. •To avoid latency, try to keep the recording-time as short as possible

  5. •When using a SLR, tilt up the mirror if possible

  6. •Please consider that satisfying results from most SLR‘s as well as from cameras with focal-plane shutter can only be obtained up to the 1/125sec. Thereafter, the time is regulated by the distance of the slit between the two curtains, wich doesn‘t affect the shutter release sound very much and therefore can‘t be recognized in the waveform !




Do you have any problems or questions regarding this App ? Then don‘t hesitate contacting me !


My name:    Lukas Fritz


Email:          LukasFritz@gmx.net