Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Using iPhone 4 as Light Meter to Calibrate a Digital Camera

DIY Book Scanner Skunk Works. Share your crazy ideas and novel approaches. Home of the "3D structure of a book" thread.
univurshul
Posts: 496
Joined: 04 Mar 2014, 00:53

Re: Using iPhone 4 as Light Meter to Calibrate a Digital Cam

Post by univurshul » 03 Aug 2010, 12:02

excellent. I'll look at this further, but it does sound like I need to offload the image just to see the values.

univurshul
Posts: 496
Joined: 04 Mar 2014, 00:53

if the f/number is 'x', then the other settings = 'y,z'

Post by univurshul » 14 Aug 2010, 15:48

One cool thing I've discovered about the Light Meter app is how it calculates around preset, unchangeable f/number settings on my digital camera.

So, say the app's exposure meter reads the ideal f/number is 2.5, but the digital camera is positioned and ready to shoot the book; the cameras won't allow the f/number to be set below 4.5.

All I need to do on the app is move the number to 4.5. This changes the ideal shutter speed to 1/13s and, the ISO remains the same at 80. By following the exposure calculator on the Light Meter app, and changing the Canon's setting according to these readings, it produced an even clearer set of images--with improved contrast ratios--as opposed of my earlier "closest settings" approximations.

Very useful app.

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