Modifier les paramètres de l'appareil photo

Bonjour
Voici le code qui permet de modifier les paramètres de l'appareil photo sous Android:
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
mCamera.setParameters(parameters);

/*
Important: Call startPreview() to start updating the preview surface. Preview must be
started before you can take a picture.
*/
mCamera.startPreview();
}