aforge.net. in class VideoCaptureDevice, DesiredFrameSize property is not working for me.

Hi Friends
class VideoCaptureDevice, DesiredFrameSize property is not working for me, tell me where is mistake in (1)? same as (1) problem I also want to set custom DesiredFrameRate property.
(1):

videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice );
VideoCaptureDevice videoSource = new VideoCaptureDevice(videoDevices[0].MonikerString );
videoSource.NewFrame += new NewFrameEventHandler( video_NewFrame );
//
selectedCamera.DesiredFrameSize = new Size(200, 200); //no any result
//
videoSource.Start( );
 
private void video_NewFrame( object sender,
        NewFrameEventArgs eventArgs )
{
   MessageBox.Show(eventArgs.Frame.Size.ToString());  //message box shows (640,480) not as configred       
 //...
}

(2)its working fine
i also tried the following and it is working fine on the frame.

public static ResizeNearestNeighbor size = new ResizeNearestNeighbor(200,200);
//
Bitmap bitmap = size.Apply( eventArgs.Frame);
   MessageBox.Show(bitmap.Size.ToString());  //working fine
//..