I have been using a buddies spotting scope all summer and have decided it is a great tool for scouting and want to get my own. He has a Leupold SX-1 with 20-60x magnification and 80mm bell. My question is how much does the bell size affect light? Could anyone put a guess on the amount of time I would lose from going to a 60mm bell? 5 minutes...10 minutes? I would like to go to a slightly smaller scope for the ease of pack ability.
