Aleph 3 and Lux V focus question.

[Lunal_Tic]

Does it make sense that a Lux V in a Aleph 3 would have no hole in the beam up to about 1M but have a hole after that? Also when I try to adjust the LED to get rid of the hole at longer distances it seems less bright. Do I need my eyes recalibrated or is this how things work?

TIA,
-LT

 

[wasBlinded]

A lot of discussion on Lux V and optimal focus in the past, especially WRT the U2.

The consensus seems to be that at optimal focus for best throw, there will be a slight donut hole. You can get rid of the donut hole by defocusing, but at the expense of throw. Looks like you've discovered all of these things yourself!

 

[Lunal_Tic]

wasBlinded,

Thanks for the info but I thought it was the other way around hence the question. I've got a L6 and it seems to throw well and there is no donut. The A3 however has a shorter reflector so I thought the donut would be close up not at distance.

Guess I'm just confused, not surprised about that though. /ubbthreads/images/graemlins/grin.gif

-LT

 

[Kiessling]

Hey LT ... all Luxeon lights that use a reflector (III and V alike) do have a hole in the beam when viewed very close to a surface (e.g. a white wall) that disappears with the growing distance. this is normal and a sign of working photon redirection by the reflector.

The LuxV ... when in perfect focus, like already pointed out, you'll see the donut and have the best possible throw. You defocus ... no donut and a bit less throw. The best defocussing method seems to be a small shim between the reflector and the LE.

bernie

 

[Lunal_Tic]

Thanks Kiessling,

I knew about the close up part but it just seemed weird to me that from 30cm - ~1.3M there is no hole. It only shows on either end of that scale. The other odd thing is the performance of the L6 to which I'm comparing it. No hole there except close up ~10cm but it seems more diffuse at 2-3M.

BTW, the A3 setup stomps the L6 but I kind of figured it might. I haven't done any testing past 3M but I'd guess it's about double the light of the L6.

-LT

 

[Kiessling]

Hm ... /ubbthreads/images/graemlins/icon3.gif ... my wisdom ends here. Guess we'll have to wait for someone with a bigger head /ubbthreads/images/graemlins/grin.gif ...

Yepp, I have a DB917 LuxV in an Aleph3 head that eats the SF LuxV lights alive ...

bernie

 

[Lunal_Tic]

Thanks Kiessling,

This is a W or X bin, can't remember which, sitting on a BE4 running about 1.1A thru a MJ converter so yes it "eats the SF LuxV lights alive". /ubbthreads/images/graemlins/grin.gif

-LT