Shutter speed iPhone app

[Mainecoonmaniac]

I have the Shutter Speed app for iPhone and I find it hard to use. Maybe someone can make an app that uses the camera that actually measures the shutter with the camera by measuring duration of the light instead of using the sound of the shutter?

[rawhead]

It's probably not very practical for higher speeds. In order for something like that to work, you'd need to be using the CMOS sensor in the iPhone in "video" mode, where it's constanly exposing and "waiting" for the light to hit the sensor. And since the frame rate for iPhone cam is 30fps, reallly the fastest shutter speed you can measure using that is 1/30s. I'm guessing that the Shutter Speed app you have can go faster than that?

[M Carter]

I was thinking this over the other day - something like this would likely work with the slowest iphone "shutter" speed, and measure how much of the light is scanned. The iPhone has such a low scan rate for the sensor though (that's why you get "jello" when you move the phone - things like phone poles become slanted). I doubt the sensor is scanned fast enough to do faster shutter speeds.

Ever slide a document around on a xerox machine or scanner bed while the light is moving across the glass? That's essentially what happens with digital sensors (they're moving much faster, but same effect).

But the calculation would likely be based on "size" - how many rows of pixels get illuminated, divided by the sensor scan time. Which would likely change based on distance between the shutter and the phone's camera. My best guess anyway.

[Mainecoonmaniac]

So many smart APUGers! So how useful is using sound sound from a clicking shutter to measure speed like the iPhone app?

[rawhead]

I've done shutter speed test using sound recorded with a microphone connected to a computer. It's pretty good up to 1/60s or so. Better option is this product: http://www.ebay.com/itm/Camera-shutt...item230a1554f6

This actually uses a photodiode to detect the increase/decrease in the amount of light, THEN converts that into sound waves sent to the computer. With this I can measure up to 1/250s reliably, and pretty good at 1/500s. The specs say it can do 1/1000s, which I'm finding hard to do. Regardless, you really can't beat the price

[cliveh]

I have the Shutter Speed app for iPhone and I find it hard to use. Maybe someone can make an app that uses the camera that actually measures the shutter with the camera by measuring duration of the light instead of using the sound of the shutter?

Wash your mouth out with soap and water.