Show me the way...lens/optics types explained.



Newly Enlightened
Sep 17, 2021
Page, AZ

I've been searching google for some education on the different ways that LED flashlights are focused, refracted, and generally managed (the light that is). But I havent been able to sort out what the different types/styles of lenses and optics are. This forum is referred to the most, but I have yet to find any thread or posts that are educational about how these things work (optically) and what they look like. I'm trying to educate myself as much as I can. My kid has a science fair this Fall and wants to shine a light on the dark side of the moon. I understand this isnt feasible, but I'm not ready to crush his spirit yet and would rather let the cold hand of science do that :) Regardless, it will be a fun project with him to build the farthest shining light we can in his quest to "have a full moon all the time Dad."



Nov 21, 2015
Terre Du Lac, MO.
Welcome to the forum. I discovered Page, AZ on a motorcycle tour in 1976. One of my favorite places in the country.
Others will chime in with the optics question.


CPF Supporter
Aug 9, 2015
My own little Idaho
A basic flashlight puts out light through a lens. Ok, that's the starting point.
Now how that light reaches said lens is where things go in numerous directions.

A typical flashlight reflects light off of a reflector, more times than not, a shiney one. It might be mirror smooth or have texture often called orange peel because, well the texture looks like a chromed orange. That light goes through a flat, clear disk made out of plastic or glass. Plastic is for shatter proof or reduced production cost. Glass is more scratch resistant than plastic typically.

A flashlight that uses an optic is like a telescope in one respect. It focuses light through a shaped prism to achieve a certain goal. Straight line without much spill, a very wide beam or a combination. It is typically a plastic material. Some are frosted, some are covered in honeycomb shapes and some are clear.

Enter the COB light. Chip on Board. That light has a bunch of tiny LED's that all shine in unison so they appear very bright while providing even lighting from side to side and in the center.

If anything, the way to light the dark side of the moon would be to shine a very bright light on a nearby satellite and that light reflect back to the dark side of the moon. But then again, science being what it is there may be an optic out there that can bend light. (shrugs shoulders)

Welcome aboard.