Being a complete newbe, I've no idea how "bright" a given number of lumens translates to be in the real world.
I'd like to find a table that shows what lumens you would expect for various tasks. I think it might go a little like this:
*1-2 lumens: Finding a keyhole, close range work (within arm's reach), close reading, maybe a supplement to dark-adapted vision finding your way around a room. Some mini incandescent keychain lights admit to this level.
* 5-10 lumens: Indoor use, close inspecitions, map reading, testing eyes; the 2 AAA penlight with a #222 prefocus bulb is in this range.
* 15-30 lumens: General household indoor use, moderate range outdoor use ( a few yards); this is the light range that the 2 D cell plastic light with a prefocus bulb generates.
* around 50 lumens: Walking a good trail at night, finding your way in unfamiliar surroundings.
* 60-200: So-called "tactical" lights; identify a man-size target at firearms range. Power LEDs can give 100+lumens from an AA cell. In my experience, 100 lumens can light up a small suburban backyard (say, 60 feet x 30 feet) and verify the yard is free of the neighbor's cat.
* 200 lumens and up - Outdoor, moderately long range, search and rescue - you can go up to several thousand lumens in a hand-carried light but I think anything much over 500 is a rather special purpose tool.
* 500+ lumens- - I understand night-time orienteers use high-power lamps in this range for running unfamiliar trails in the dark.
Don't take these numbers as anything other than the centers of pretty broad ranges.
Bill