I'm looking into buying a new hand held light for this season, and I really like the surefire lights. My problem is, all them are rated in lumens? I'd like to know what a lumen is compared to candlepower. The model I like is 100 lumens, and I don't have a clue how bright this is. For example, how does a 100 lumen light compare to a 3 or 4 d-cell mag light? any help or advice would be greatly appreciated. thanks in advance