Bolster
Flashlight Enthusiast
I like the Irix Icon II as a backup headlamp. Where else can you get 1xAA, 50 lumen, and a dial potentiometer for a little over $20? As Carrot said, "...the poor man's SF Saint."
However for my use it has a fatal flaw...the narrow beam spread. Sort of like looking down a tunnel. The beam has a gradually receding margin, which makes actual measurement difficult, but if you try to measure the edge of the beam where it's about 50% as bright as the center (judging by eye), I calculate the beam about 24 degrees, across multiple trials. Might be perfect for reaching your feet (a trail hike at night), but it's pretty darned narrow for reaching the ends of your arms (hand-work).
So after reviewing the standard CPF options...bead-blastiing, grinding the tops flat, applying an opaque epoxy, sanding the LEDs, or using frosted glass spray, I chose the easiest for this job...the spray. First, a before shot:
As a "control," I pasted some frosted "invisible" style scotch tape across the LEDs and remeasured the beam spread...that took the beam spread to 31 degrees, averaged across several trials. I was curious whether the spray would do as well (or perhaps worse) than tape.
Then using calipers, I made a paper mask in Illustrator. (If you want a copy of this mask to do the same on your Icon II, just PM me and I'll send you a PDF of it.) Cut out the tiny circles with an exacto knife, and tape in place over the LEDs. This is a stupid photo but you get the idea:
Cleaned the tops of the LEDs with alcohol, then sprayed with $5 can of Rust-Oleum Frosted Glass Semi Transparent finish. Wait 2 minutes, and hit it again with another coat, as per instructions. Wait 10 minutes and it's dry, peel off the mask, and here's what it looks like afterwards:
Now for the measurements...the beam was now spread enough I found it very challenging to find where the 50% dropoff point was. At 24" from the wall I was measuring, across 5 trials, 18, 22, 21, 20, and 20 inches of diameter. That's a lot of variance, showing how much trouble I was having finding the "50% edge" of the beam. (But it sure was wider than the 9.5-10" dia beam I was measuring at first.) Take the average, trig the numbers, and that comes to 45 degrees of beam, for the central portion, then fading "spill" to the sides. So in use, it seems somewhat wider. It passes the reading test. I can read a book without turning my head to re-aim the beam. Thumb-up.
It's more useable for my purposes now. Obviously I've lost some throw. I can't tell how many lumen I've lost, but my hunch is less than with the tape. When I use it in the dark it still seems "plenty bright," which was also my opinion pre-modification. I expect the finish to wear off with time, which will mean another application of spray. I don't know how tough it is, actually. Maybe it'll be better than I think.
Finally, it's interesting to note that the frost spray is considerably more efficient at spreading a beam than is the invisible-style frosted tape. I wasn't expecting that.
Beam looks the same before and after, just wider. Which means I have to re-aim it less often. And I can no longer pick out blue and yellow artifacts as before. It's still a directional flood, but I now consider it a decent backup for my H501s. In fact, I may get another.
(Posted here because I thought the headlampers would find it more interesting than the modifiers.)
However for my use it has a fatal flaw...the narrow beam spread. Sort of like looking down a tunnel. The beam has a gradually receding margin, which makes actual measurement difficult, but if you try to measure the edge of the beam where it's about 50% as bright as the center (judging by eye), I calculate the beam about 24 degrees, across multiple trials. Might be perfect for reaching your feet (a trail hike at night), but it's pretty darned narrow for reaching the ends of your arms (hand-work).
So after reviewing the standard CPF options...bead-blastiing, grinding the tops flat, applying an opaque epoxy, sanding the LEDs, or using frosted glass spray, I chose the easiest for this job...the spray. First, a before shot:
As a "control," I pasted some frosted "invisible" style scotch tape across the LEDs and remeasured the beam spread...that took the beam spread to 31 degrees, averaged across several trials. I was curious whether the spray would do as well (or perhaps worse) than tape.
Then using calipers, I made a paper mask in Illustrator. (If you want a copy of this mask to do the same on your Icon II, just PM me and I'll send you a PDF of it.) Cut out the tiny circles with an exacto knife, and tape in place over the LEDs. This is a stupid photo but you get the idea:
Cleaned the tops of the LEDs with alcohol, then sprayed with $5 can of Rust-Oleum Frosted Glass Semi Transparent finish. Wait 2 minutes, and hit it again with another coat, as per instructions. Wait 10 minutes and it's dry, peel off the mask, and here's what it looks like afterwards:
Now for the measurements...the beam was now spread enough I found it very challenging to find where the 50% dropoff point was. At 24" from the wall I was measuring, across 5 trials, 18, 22, 21, 20, and 20 inches of diameter. That's a lot of variance, showing how much trouble I was having finding the "50% edge" of the beam. (But it sure was wider than the 9.5-10" dia beam I was measuring at first.) Take the average, trig the numbers, and that comes to 45 degrees of beam, for the central portion, then fading "spill" to the sides. So in use, it seems somewhat wider. It passes the reading test. I can read a book without turning my head to re-aim the beam. Thumb-up.
It's more useable for my purposes now. Obviously I've lost some throw. I can't tell how many lumen I've lost, but my hunch is less than with the tape. When I use it in the dark it still seems "plenty bright," which was also my opinion pre-modification. I expect the finish to wear off with time, which will mean another application of spray. I don't know how tough it is, actually. Maybe it'll be better than I think.
Finally, it's interesting to note that the frost spray is considerably more efficient at spreading a beam than is the invisible-style frosted tape. I wasn't expecting that.
Beam looks the same before and after, just wider. Which means I have to re-aim it less often. And I can no longer pick out blue and yellow artifacts as before. It's still a directional flood, but I now consider it a decent backup for my H501s. In fact, I may get another.
(Posted here because I thought the headlampers would find it more interesting than the modifiers.)
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