Need some insight: light filters

[gmf2010]

I've decided to purchase a red filter for my OLight M20, mostly for use at night. I see there is a diffuser and also a green filter available for the M20 as well. My question is, between the two (in addition to the red filter), should I grab the diffuser or the green filter?

I've done some research, but don't really understand the exact use of the green filter. From what I gathered, it's best for use with night vision (which would sway me towards the diffuser, but I have also read conflicting statements about whether or not it makes blood and/or blodily fluids stand out better.

I'd appreciate any insight you guys have to offer on this topic.

Thanks alot

 

[PhantomPhoton]

The diffuser is a very useful accessory to have with your favorite flashlight. I'd go for that one.

The use of color filters imho is kind of pointless when using most LED flashlights. If you want red light get a red LED light is what I say . Current generation LEDs give out just enough in the proper wavelengths to appear white to our eyes. They really dont' have a lot of output in red, blue-green and UV. It just isn't efficient to run a high powered LED under a filter trying to get these light wavelengths.

As for green, unless you have a very specific use there is no real reason to have a green filter. The human eye is most sensitive to light at ~555nm, yellow-greenish. So around this wavelength we need the least power/ light output. Also sometimes you'll see some seller claiming special night vision something or other... generally it's just hype by someone who has absolutely no idea what they're talking aobut. A coupe colors have beneficial uses for covert or night vision tasks, but which one you want really depends on what you want to do. Ya gotta use the right tol for the right job.
Blood, fluids, etc are usually more visible in the blue and UV part of the spectrum. Again with an LED light it's better just to buy a UV LED light and glasses.

 

[StarHalo]

+1 for no filters on LED lights; if your flashlight is only emitting 10% of its total light output in the red part of the spectrum, then putting a red filter on it will make it only 10% as bright.

There's all kinds of very inexpensive colored LED flashlight choices out there, from the Photon keychain light (http://www.photonlight.com/Photon-F...-Flashlights-p/fm-led-keychain-flashlight.htm), the super-simple Pak-Lites (http://9voltlight.com/products), and the astronomer's favorite, Rigel Systems (http://members.cox.net/rigelsys/flashlight.html).

 

[Oddjob]

I have found a really low setting preferable to using a red light at night. Using red to preserve night vision is fine but for me and many here a really low level is just as good. Also as it has been mentioned it would be more efficient gettting a red LED vs using a red diffuser.