Browning trail camera - Browning Trail Cameras BRW Strike Force HD BTC5HD

Camera take excellent pictures day and night. However, the night pictures at times are too dark to make out anything. Have not quite figured out why the night pictures are very good at sometime while other times they are just a dark screen. It might be the distance based on one camera that is always good, however, the capture is a hog trap which is only 10 yards away.