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10-21-2019, 02:43 PM   #1
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Anyone use "Photoplug" shutter tester?

I know there are a couple of ways of checking your shutter speed using a CRT TV or a record turntable.... admittedly I've not actually tried those. Looking online at other methods I noticed a device called "Photoplug" which seems to be a small light sensor which plugs into your smartphone headphone jack. Details here:- Filmomat ? PhotoPlug..PhotoPlug

I was just wondering if anyone had tried this and if it was accurate?

10-21-2019, 06:06 PM   #2
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This will work only for cameras where you can access the area behind the shutter (as they say in their material: "Open/Remove the camera back")

It will not work for most digital cameras. For that, you need something like my LED flasher: True Shutter Speeds compared to Nominal Shutter Speeds - Actual Measurements - PentaxForums.com

If you are handy with circuitry, I'd be glad to share my design.
10-21-2019, 06:42 PM   #3
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QuoteOriginally posted by AstroDave Quote
This will work only for cameras where you can access the area behind the shutter (as they say in their material: "Open/Remove the camera back")

It will not work for most digital cameras. For that, you need something like my LED flasher: True Shutter Speeds compared to Nominal Shutter Speeds - Actual Measurements - PentaxForums.com

If you are handy with circuitry, I'd be glad to share my design.
Well this is posted in the Film SLR forum...
10-21-2019, 07:03 PM   #4
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QuoteOriginally posted by boriscleto Quote
Well this is posted in the Film SLR forum...
My bad!!

10-22-2019, 07:06 AM   #5
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I've not ever used it but it looks like a solid concept.

The only minor accuracy issue would be caused by the sampling rate of your particular phone's microphone circuits. Some phones only sample at 8kHz which is adequate for telephone calls but would lead to Photoplug inaccuracies for shutter speeds faster than 1/1000.
10-22-2019, 10:22 AM   #6
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QuoteOriginally posted by photoptimist Quote
I've not ever used it but it looks like a solid concept.

The only minor accuracy issue would be caused by the sampling rate of your particular phone's microphone circuits. Some phones only sample at 8kHz which is adequate for telephone calls but would lead to Photoplug inaccuracies for shutter speeds faster than 1/1000.
I'm not an electronics or mobile phone expert but would a device connected to the headphone jack use the microphone circuit?

Regarding using this device with the film back open, I think it will only work with older mechanical SLR's like my ME Super, MX and K1000. It won't work with my modernish Canon EOS 3 because the shutter doesn't operate normally with the back open.
10-22-2019, 10:58 AM - 2 Likes   #7
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QuoteOriginally posted by Vendee Quote
I'm not an electronics or mobile phone expert but would a device connected to the headphone jack use the microphone circuit?
The jack on a smartphone includes an extra contact for the microphone on a headset. The Photoplug is using that microphone connection to send a signal into the phone. The app then samples the electronic signal coming through the jack as if it were audio and interprets the waveform to detect when the shutter opened and when it closed.

The microphone circuit in a smartphone can be used to measure any time varying signal within the frequency and voltage limits of the circuit.
10-22-2019, 02:30 PM   #8
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QuoteOriginally posted by photoptimist Quote
The jack on a smartphone includes an extra contact for the microphone on a headset. The Photoplug is using that microphone connection to send a signal into the phone. The app then samples the electronic signal coming through the jack as if it were audio and interprets the waveform to detect when the shutter opened and when it closed.

The microphone circuit in a smartphone can be used to measure any time varying signal within the frequency and voltage limits of the circuit.
Thanks for the explanation............ always learning


Edit. And just googled my phone and it appears to sample at 48kHz so should be fine.

10-22-2019, 02:50 PM - 1 Like   #9
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QuoteOriginally posted by Vendee Quote

Regarding using this device with the film back open, I think it will only work with older mechanical SLR's like my ME Super, MX and K1000. It won't work with my modernish Canon EOS 3 because the shutter doesn't operate normally with the back open.
Depending on the camera, you may be able to fool it.
With some cameras, the door pushes a switch in the body to let it know itís closed. Jamming something gently into the hole will let the camera operate normally.
Some cameras need the film to wind, so you have to jam the switch and then spin the film sprocket between frames.

-Eric
10-23-2019, 12:52 AM   #10
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QuoteOriginally posted by TwoUptons Quote
Depending on the camera, you may be able to fool it.
With some cameras, the door pushes a switch in the body to let it know itís closed. Jamming something gently into the hole will let the camera operate normally.
Some cameras need the film to wind, so you have to jam the switch and then spin the film sprocket between frames.

-Eric
Wow, that worked thanks. I had notice 3 electrical contacts inside the back door which mated up with the body when closed and I had assumed that these needed to be made to allow the shutter to fire but it seems that these are for the operation of the controls. prodding something in the door catch mechanism allowed the shutter to fire normally with the back open.
10-30-2019, 08:36 PM   #11
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I think I've seen this before (or something very similar) a few months back
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