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Drew Bedo
20-Mar-2012, 08:21
I am an e-idiot (and maybe an i-idiot too). with that said: Is there a way to use an iphone or ipad to test the adduracy of a leaf shutter lens?

I would hope that there is some way that reads out directly in fractional shutter speeds, or even miliseconds.

Anybody know how or have any ideas on this?

redu
20-Mar-2012, 08:39
Very nice idea. I am an anti-apple. But there are some free audio recorder applications with wavefrom editing for Androids. So if the shutter sound is recorded i believe the duration can be measured/read from the wavefrom. 1/500 is only 500Hz. Hmmm.. Later today I'll give it a try on my HTC.

domaz
20-Mar-2012, 19:29
Someone has developed a light meter app for the iPhone but it's questionable whether the iPhone's built-in light meter would have a high enough response rate to act as a shutter tester. I would bet it doesn't. Using a light sensor hacked to the audio port seems like the best solution- you mine as well just use a PC if you go that route though, better documentation and it's been done before.

Tim Meisburger
20-Mar-2012, 21:44
Interesting you raise this, as I was wondering yesterday if there is an app for Android for testing shutters. I could not make one either, but it seems to me it should be possible. But what do I know?

Vincent Pidone
22-Mar-2012, 05:23
Maybe some information here:

http://wordpress.crazylab.de/2012/measuring-the-performance-of-dslr-cameras-and-why-the-iso-setting-could-impact-the-burst-length/

Drew Bedo
22-Mar-2012, 05:24
sopme good stuff here.

REdu: Did you try it out?

domaz: I'm looking for a way to check the shutter in the field . . .or at least as I set up for a shot in-studio. I don't think the iOhone meter app works well enough for LF imaging.

On another forum someone suggested a photodiod pligged into the audio socket for a light sensor that would make an audio signal that could be measured.

I envision setting up the camera and mounting a lenscap modified with the light sensor, then tripping the shutter for a quick check. It would just be another correction to the basic exposure . . .like filter factor or bellows correction.

Arne Croell
22-Mar-2012, 09:27
Yes, there is a way for slow speeds up to 1/125, if you know how an oscilloscope works. I use an app called "Oscilloscope" using the microphone, and in trigger mode the shutter sound shows the opening and closing - one can even see the bounce back of the shutter leaves for both the opening and the closing process. After determining which peaks are the actual opening and closing, counting the time on the oscilloscope image is easy enough.