How to reduce light loss in a zoomie torch when zoomed in

[EasyB]

A precollimator lens is a good way to collect more light into the beam. With proper lens selection and placement, the beam size (in spot mode) is 2-3 times the area and within 10% of the original beam lux. The light collection efficiency in aspheric lens lights (in spot mode) is typically very bad, around 25%. A precollimator lens can increase the light collection by 2-3 times.

Here are a couple lights I’ve made with precollimator lenses:

Converting Convoy C8 to Fresnel lens thrower

This project was motivated by the success of my UF-1504 with pre-collimator setup. When comparing the beams of my 1504 with dedomed XPG2 and C8 with smooth reflector and dedomed XPG2, the hotspots were nearly the same size even though the 1504 has ~2.5x the beam lux. The double lens setup is apparently better at getting more lumens in the actual hotspot. The C8 reflector is still getting a lot of the light downrange, but a lot of it is located in the less bright corona. So I wanted to put a dou…

Light lost in aspheric lens flashlight

Hello everyone: I have a UF-1504 host on the way from mtnelectronics, so I’ve been thinking about how to optimize the flashlight. My goal with this flashlight is of course to have a lot of throw (cd), but I’m concerned about the low light extraction efficiency due to the light not collected by the lens when it’s in focused “spot mode”. So I am planning on using a small collector lens very close to the LED to collect a good portion of the light that would just be lost. My understanding is that …

This is the precollimator lens I used for my C8 fresnel lens conversion:
http://www.kaidomain.com/p/S020945.18mm-Optical-Glass-LED-Lamp-Lens-1pc

Depending on the size of your light, you might need a smaller diameter lens.