Just curiouse if there is any way to reduce the rainbow affect of an aspherical lens? My BFL MAG's die image is pretty clean, but there is a slight blue/purple rainbow around it. Is there any way to clean it up or is it just because of the lens? What causes this affect?
How do you reduce rainbow affect?
- Thread starter LED4LYF
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That's called chromatic aberration if I'm not mistaken. That's the same thing that happens with camera lenses that do not correct for such problems. High-end lenses use very low dispersion optical elements to make different wavelengths of light converge closer to the same point. Here's a brief explanation with ilustration:
http://www.nikonusa.com/Learn-And-Explore/Nikon-Camera-Technology/ftlzi4z6/1/Super-ED-Glass.html
I'm afraid that's a physical property of the lens design and material that it's made of.
http://www.nikonusa.com/Learn-And-Explore/Nikon-Camera-Technology/ftlzi4z6/1/Super-ED-Glass.html
I'm afraid that's a physical property of the lens design and material that it's made of.
wyager
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I think it's basically unavoidable. It has to do with the color peaks from the LED and refraction angles.
It's unavoidable, the different waveleghts focus at different points due to chromatic abberation as mentioned above. Since the LEDs we use have a broad yellow emission and a sharp royal blue peak, you get your good looking area with the mix of yellow and blue making white, and then the blue halo of the blue LED underneath the phosphor. If you were using a broadband source (hot wire or arc lamp etc...) you would have a few different colors on the outside if your abberation was bad enough.
You can fix it if you had an achromat doublet/triplet to help eliminate the abberation.
Thor labs has some spherical acromats for not *super* horrible amouts of money, ($113 for a 50.8mm dia x 75mm EFL lens) but you would probably end up spending a bunch if you made your own lens system to get the super narrow beam the BFL gives you.
Edmund optics has a 25mm dia x 30mm EFL Achromat Aspheric lens for $95,
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2953
could be useful for a mini thrower :laughing:
You can fix it if you had an achromat doublet/triplet to help eliminate the abberation.
Thor labs has some spherical acromats for not *super* horrible amouts of money, ($113 for a 50.8mm dia x 75mm EFL lens) but you would probably end up spending a bunch if you made your own lens system to get the super narrow beam the BFL gives you.
Edmund optics has a 25mm dia x 30mm EFL Achromat Aspheric lens for $95,
http://www.edmundoptics.com/onlinecatalog/displayproduct.cfm?productID=2953
could be useful for a mini thrower :laughing:
