LED optics explained

[jc85]

http://reefbuilders.com/2010/01/27/led-optics-explained/

Very good article for those diying their LED fixtures.

So what is the bottom line from all of this? For Littlejohn, there are two significant takeaways from his post.

“On shallower tanks, I’m a proponent of using straight LEDs without secondary optics,†he states. “I’ve found that achieving a sufficient amount of light for high-light corals is possible, there will be no flashlight effect, no spotting, and more uniformly colored shadows.â€

What exactly is a sufficient amount of LED lights for light-intensive corals you may ask? Littlejohn recommends a LED density of around 24 LEDs per square foot for 10- to 12-inch deep tanks, 36 per square foot or 12- to 18-inch tanks and 48 per square foot for tanks 18 to 24 inches deep using a nominal drive current he outlined in the previous post here at Reef Builders.

“On deeper tanks over 24 inches, I like to add a mix of secondary optics to the LED array. I’ve observed that a relatively small number of secondary optics can provide enough extra light penetration while minimizing spotting and colored shadows,†he says. “It may take some trial and error, but I believe a good starting point is to cover 15 to 25 percent of the LEDs with a good secondary optic, and LED densities of 54 or even 60 LEDs a square foot may be required, at a nominal drive current.â€

Cheers

JC

[sherman]

Very good guide line for DIYers who always wonder if they should use the Lens

[RockyBoy]

Good read for those DIYers.