How do I get past these letters that require camera light?

I keep opening these letters throughout the game and a little message pops up repeatedly at the right saying "Direct the rear camera toward a bright light." I do so, and nothing happens. I really don't understand what else I can do. It seems like I do this for like 10 minutes before it randomly decides to let me turn the circular thing. What the hell am I doing wrong? This feature has been extremely frustrating.

Solution 1:

I've had trouble with this one as well.

What you're missing is once you're pointing at a bright enough source, you need to turn your Vita around, like a steering wheel (spinning the screen) until you see the small handle you need to turn.

This is mentioned somewhere along the game, but isn't very clear during this so-called mini-game.