hey all,

does anyone know what the angle of the main hot spot for a 60 degree lens on an xr-e Q2 is..

i understand that the optic multiplies the light by a certain amount but i also understand that it wouldnt put out a perfect circle of light, so there would be 60 degrees of flood but how many degrees of light..

and are 60 degree lenses enough to keep a clam at roughly 22" deep??

Lenses are rated as FWHM, Full Width Half Maximum. What that means is that at 60 degrees, you are at 50% intensity. The "hotspot" will change from blue to white LEDs. The hotspot on Cree optics is pretty wide, so I wouldn't really worry to greatly. This is one reason why we have fairly tight spacing, so the overlap will smooth out hotspots.

60 degree optics at 22" should just about be able to keep most clams when run at 1000mA.

so art the outer edge of the outside line of light is half as bright as the center of the hotspot??? i thought it would be less than that.. i suppose it just looks that way in photo's..

is there a way to work out like Half Width intensity.. or is that just 75%

Unless you take very detailed measurements, there really isn't a good way to estimate it. Why such an interest in this?

I just noticed that you mentioned that you were looking at Q2 cool whites. You would need tighter optics for a clam with that LED. If you go to Q5s, 60's will be fine for clams.

really there is only like 24 lumens at the most difference at 350mA.. not sure at 1000mA

Doesn't sound like much, but it's a 25% difference. That's over a 70lm difference at 1000mA (160lm vs. 225lm) That makes a pretty good difference in PAR.