adjusting aspheric lens

Flashlight Modding and DIY Parts
1

Hi !

how do i adjust a aspheric lens to get a (near) parallel beam?

played around with the zeusray and some other plastic lenses poining at the wall @2m and got a sharp image of the die
but outside (raining) i see the beam is not parallel - its more like a cone…

need some inputs please!

thanks
Martin

2

You can't. A parallel beam is impossible, optics principle.

Adjust the lens to make the smallest possible cone (projects the die ob a far away target), that's the best you can get.