30mm vs 26.5 vs 20mm pros/cons

Hi all-

after lurking for quite a while I had to post this question.

Based on what I learned here, I have modded a mag D cell into a 3x3w bike light using a buckpuck, nx-05 optics and a 14.4 watt drill battery. Using my wood lathe and a rigged chuck, I took out the threads on the inside of the head where the flashlight would go, chopped off the tail and epoxied it in where the end rounded out the line of the head. I've seen pictures here somewhere of some very similar here somewhere. Other than wiring 2 of the LED's reverse and getting a nice purple hue out of them/ubbthreads/images/graemlins/mad.gif everything works well.

Anyway, version 2 has been gnawing in my brain for a while and I'm going full custom housing this time. Very similar to the EL bike lights, only with a solid back and seperate disc heat sink. Imagine an aluminum spraypaint can lid with fins and a ledge for the heat sink and you've pretty much got it right.

Since I'm going this route I haven't figured out 3 or 4 LEDs and the optics have me wondering. I like the buck puck although I confess I have nothing else to compare it to. Don't need multiple power levels, etc., just straightforward stuff.

Sooo... what are the advantages and disadvantages to the different optics? I need much more spot that flood or spill since I stick to the road, and need plenty of throw to see what's ahead. I'm kind of leaning toward a 3 spot 1 medium setup, just wondering which optics or combo of sizes would produce the desired results.

Thanks!!

Well, with a custom setup rather than just modding something you can do more exciting stuff. SO:

How about a 2 degree 50mm plus a 26.5 mm 4 X 25degree linear optic with horizontal orientation? That will give you the best throw: It will light up way ahead as well as a wide swath of your path and the sides, without wasting lumens lighting up the sky above as you would with a circular wide angle optic.

Give you longer runtime on your batteries too, compared to using 3 or 4 Luxeons.

Would the one 50mm outperform 2 or more emitters plus optics? If 2 are better for a little more, I would go for that. I don't mind it being a little larger than "normal" (as if there is a normal for custom bike lights!) but starting at 50mm may make it a little large. Plus, in my mind i can't see around it being more complex with such a disparity between the optics. I would like to KIS for this S as much as possible.

I have thought about the 4 x 25 degree, using a wedge or beveling part of the H.S. to use it vertically with the top "edge" of the 25 degrees projecting straight out. That would give some light right in front of my wheel to dodge last minute obstacles (glass, rocks, wire, etc).

I have notice that my light picks up reflectives (road signs, glass) extremely well and leaves the road surface looking flat, with little dimension. It's hard to distinguish smaller rocks from the road, maybe the 4x25 would help

For "throw alone" I'd say that the 50 mm would outperform two of any of the other optics.... although the 30mm Fraen might come close, and Entendu has a 42mm mirror optic that might do as well. Whether it would be the best overall for your particular needs though, I can't really say. And you might consider a reflector setup for your distance light. I have no real experience or recommendations with that though.

You might be able to decide for yourself before you commit to any specific plan by looking at THESE BEAMSHOTS