android camera get light sensor value
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I know how to get a lux value from the light sensor 

    android.hardware.sensor
however, i saw an app on the market 
[light meter tools][1]


  [1]: https://play.google.com/store/apps/details?id=lightmeter.hardware.lightsensor&feature=search_result#?t=W251bGwsMSwxLDEsImxpZ2h0bWV0ZXIuaGFyZHdhcmUubGlnaHRzZW5zb3IiXQ..

it said it can get the value form the camera. How can it do that?

also how can i set the shutter speed and the aperture for my android camera?