My Quark AA puts out 0.2 lumens at it's lowest output. This works well if you've been asleep and need to find your way through a dark house. But if your eyes are not dark adapted, 0.2 lumens is too low to be of much use IMHO. For non-dark adapted eyes, I find something around 4 lumens to be good for night time navigation close range. 10 lumens is a good all-around useable amount of light for general purposes (but not if you need to see more than a few feet away).