oh Lordy!!! I just soiled my boxers @ that beamshot.
Awesome work, very impressed with your fabrication skills.:thumbsup:
Curious...
How come so much light is being spilled out to the immediate sides? The light thats illuminating you as you hold it... where is that light coming from? Is it being reflected back at you off the lens surfaces?
Hmm ... I don't see any pictures
You might want to consider a proper hosting site such photobucket.com (or equivalent) for your photos. It is important to CPF that images will be available long into the future, so people returning to threads for reference can still see them. Your school is not likely to want to host your images after you have left, and its server has already proved less than reliable anyway.Sorry everyone who hasn't seen the pics, you are really missing out.
I was hosting the pics on some space provided to me by my school, but the whole system seems to be down right now. I'll put them somewhere else if I need to, but I hope they will be back up sometime soon.
A short focal length lens collects most of the light from the LED and the large fresnel lens focuses it far away. The LED is actually inside the focal length of the small lens, creating a virtual image that the large lens sees. The large fresnel lens is 13" in diameter.
oo::huh: nice!
Did you just get the lenses and then put them together to get it in focus, or did you calculate it specifically and then source lenses? or both, caclulate for available lenses?
By putting the LED slightly further away from the first lens, you could probably reduce the size of the second lens at the cost of less collected light. Also a shorter focal length of the second lens could reduce the size even without changing the position of the first lens, but usually large lenses with short focal lengths are not very common.
If you're using lenses from Edmund Optics, your getting quality lenses (which have a price of cource), but the result is just great.
This actually looks much like something I'm going to do with a Luxim light emitting plasma light in the near future (still waiting for the light to arrive).
Johan
EDIT: would you care to share a picture taken from the side and of the total setup when the light is on (maybe dim it a bit not to overexpose the camera) so we can see the light path between the optics?