Yeah, you’re right.
I thought it was like 120° but it’s actually 140°
This may explain why it does considerably better (lumen / wise) than the A60.
When my camera battery is full i’ll do some shots from the screen towards the LED, hopefully it will show how much of it is actually doing the good work.
It seems the outer perimeter of the reflector is a little ambiguous though.
The contest everyone is talking about is the Annual Scratch-built Flashlight Contest which has recently closed for this year, and winners haven’t even been announced yet.
I made some nice and grainy shots facing the light from about 20 meters away, light on extremely low power of course:
Left is taken from left, middle from the middle and right from the right of the hotspot.
I conclude the outer perimeter of the parabola reflects too much inward, the ring section inside that is okay, inside that one seems to reflect a little too much outward, the middle is okay.
(The most outward perimeter is not parabolic but flat so that does nothing at all.)
Yeah looks like a bad parabola, that's unfortunate. You're getting the same effect that djozz got with the outer part of the parabola focusing inwards.
It should still work alright for a handheld flashlight, but probably won't get 1M lux :/
…and then a ring that’s okay, and than a ring that reflects outward, and then another change in angle…
Considering glueing rings on the back pushing and pulling it in shape, but…
Not sure it’s worthwhile to continue with it.
As a mirascope it’s not much good either…
From what I can tell, solar collectors are far less accurate since they don’t need to project a perfect image, they just need to focus light to a small area more or less, not a perfect point.
Even spherical reflectors will accomplish this.
I would only use a solar reflector if it is really large, like 12 or 24” and up, where the accuracy matters less.
For small sizes you need really accurate stuff, such as an electroformed or glass reflector.
I think the mirascope was the best bet
Not sure if I want to spend $50 to get a 9” mirasope shipped to me from the US and hope for better luck… I will have to reconsider.
Judging by the reflection, I think it looks pretty good actually on the ebay picture, I ordered two to play with. And I tend to think shallow is good, it catches a 90 degrees cone which is quite perfect.
So I found out that parcan bulbs use parabolic reflectors (hence the “par” ) and there are a bunch of burnt out bulbs at my old highschool.
Hopefully some time soon I can go there and pick up a few and crack the front lens off.
The reflector is glass and should be a very good parabola, and iirc it’s also a pretty shallow reflector.
If I can crack the front lens off without breaking the reflector I will be sure to post some pics of testing here