RE: Hunting and flashlights
I usually use a head lamp w/ red LEDs.
There are 2 reasons why red or green are better.
1. You're eyes dont have to adjust to the darkness going from a red or green light. Try it. You can have a red LED on and still see in your peripherals.
2. The lens filter keeps the light from traveling as far and you cut out a bunch of the light, so its not as noticeable and doesnt stand out. I doubt it has anything to do w/ if the deer can or can not see it easier.