Shutter Speed Tester - Cheap solution using your computers sound card,
freeware program and a very simple device that you can build with parts from
Radio Shack or an electronic parts store.
Do a Google Search for "Audacity" - an excellent (free) sound editor / I
borrowed this from another web site.
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My set up. I use rubber bands to hold it to the camera and what ever is
handy to hold the light up to the lens. Open the aperture fire the shutter
and record the results. |
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The working side with the Phototransistor showing. The wire on the right
plugs into the microphone jack. |
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The switch with the on switch -- if upside down it's the no switch |
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Inside lay out and battery case shown without cover. |
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Nothing Fancy and no circuit board just soldered together.
Phototransistor i.e. BPW 40 (most will work), 5 K ohm Resistor, Mono-Plug
5.5mm, Battery holder I used 2 AA, switch on/off, and a box to put it all
in. |
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The inside of my box nothing fancy. |
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The inside of my box nothing fancy. |
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I like using a led flash light but any bright light source should do |
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Turn the light on, switch the tester on, Plug the mic into the
computer start Audacity program. Open the aperture hit the record fire
the shutter and record the results. |
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I took a digital picture of my computer screen
I cocked and fired the shutter six times you can see the spikes in the
recording. The test was done on my AGFA Isolette with a Vario shutter
testing 1/25 speed |
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I zoomed in to one of the spikes and you can see a nice square wave |
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Than you can select just the square wave and measure the wave. The time
is shown on the bottom. |
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Measurement =.068209 sec which falls between 1/15 and 1/8 sec. So I'm
running a little slow ... time for a CLA. |
| Measurement Times Converted to Shutter Times 1/2 Seconds = .5
1/5 Seconds = .2
1/8 Seconds = .125
1/15 Seconds = .066
1/20 Seconds = .050
1/25 Seconds = .040
1/30 Seconds = .033
1/50 Seconds = .020
1/60 Seconds = .0166
1/75 Seconds = .0133
1/90 Seconds = .011
1/100 Seconds = .010
1/125 Seconds = .008
1/200 Seconds = .005
1/250 Seconds = .004
1/400 Seconds = .0025
1/500 Seconds = .002
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