For your pair of 8x42 monocular, the exit pupil is five.twenty five. Look for an exit pupil of 5 or larger if you must use them in low light. On an overcast working day, we look for lens brightness and eye reduction. We also Test design and weather conditions resistance https://lorenzojlifb.mybuzzblog.com/7295249/examine-this-report-on-monocular-infrared-telescope