c# - Windows Phone 8.1 app MediaCapture under exposed -

i trying capture pictures directly camera in windows phone 8.1 store app.

i have succeeded in initializing mediacapture device , take photographs black or way way under exposed.

can point me in direction of how camera auto expose , if possible trigger focus catastrophic failure when call photomanager.videodevicecontroller.focuscontrol.focusasync()?

for auto-focus use code:

mediacapture = new mediacapture(); var settings = new mediacaptureinitializationsettings(); settings.streamingcapturemode = streamingcapturemode.video; settings.photocapturesource = photocapturesource.videopreview;  await mediacapture.initializeasync(settings);  var focussettings = new focussettings(); focussettings.autofocusrange = autofocusrange.fullrange; focussettings.mode = focusmode.auto; focussettings.waitforfocus = true; focussettings.disabledriverfallback = false;  mediacapture.videodevicecontroller.focuscontrol.configure(focussettings); 

for exposure, try this:

await mediacapture.videodevicecontroller.exposurecontrol.setautoasync(true);