So I'm torn between two different bulbs at this point.

First, there is the LL T15 with a CRI of 91, but a relatively low lumen count (I can't find the specs, but similar bulbs with this high CRI's are in the 23K range) It is also a very long, but skinny bulb. I like skinny, but don't want something that long. Not a huge fan of the horizontal mount either. It will make designing my light housing a bit more complicated.

My other option is the MVR400/U/ED28. It has a CRI of 65 and init lumens at 36K. It is also only 8.25" long and relatively narrow at approx. 3" in diameter. It can also be mounted in any position (universal burn capability).

http://www.grainger.com/Grainger/wwg/itemD...emId=1611594892

Also, to be mentioned, I plan on using a reflector and would prefer to use the pro reflector from LL if possible. Anyone use the last bulb used with one of the LL reflectors yet? Any advice?

Thanks,
Josh

I can tell you that you will need the T15 shape or smaller in order to use the pro reflector (and expect the gains out of it). The ED28 shape might be shorter, but the 3.5" diameter will make it of no use with the pro reflector. My feeling is that the LL lamp is likely in the 32,000 lumen range... I could be wrong though...

cheers,
gs

what he said. the EFL of the pro reflector is 22mm. I believe the radius of the T15 is 21mm, so placing the reflector 1mm from the bulb gives best results. Any bulb with arc more than 21mm from the glass exterior will not work effectively with the pro reflector.

OK, I keep getting mixed signals on this subject and need someone to "unfuzz" my brain a bit.

So, the pro reflector is a spherical reflector, correct? so by placing the arc at the efl, we would essentially make sure that all light coming off the reflector is moving parallel to the projector light path. But we want all the light originating from a point source, so wouldn't we want all the reflected light to be returned to its source, the arc?

I guess I just feel like if light is traveling perpendicular to the collimator fres, the collimator will just change the direction that light is flowing, so that it is no longer traveling parallel when it reaches the lcd on the other side.

(This is for a split fresnel system)

I hope this makes sense to someone. I just feel like the arc should be placed at the theoretical center of the reflector sphere.

Go with that feeling. We want the bulb to be in the center of the sphere (or very close to it, I guess you can move the reflector slightly closer to the bulb which reflects the light from the edges of the arc better.

I think the term "EFL" is thrown around too much, it confuses the subject. We want the bulb to be in the center of a spherical reflector.

Spherical reflectors do not have a focal point. You cannot completely collimate light from a point source with a spherical reflector by itself.

Thanks Hirudin.

Few other questions about LL's T15 lamp.
1. What is the mounting position of the bulb supposed to be? (is mounting it vertically if it is supposed to be horizontal detrimental and in what ways?)

2. Seeing as the eballasts are currently out of stock, what kind of ballast is this supposed to take? (M59 or some other)

3. When is the next order of eballasts expected to arrive?

4. Do the eballasts require a substantial amount of heat sinking, or could I get by with just one 80mm fan above it in something like the Rorshach Military design with the ballast isolated from the heat of the bulb in its own little chamber?

Thanks again,
Josh

spherical reflectors don't have a focal point?

Au contraire! But Hirudin stated one cannot collimate light using a spherical.

ok, now I'm confused.... spherical reflectors do have a focal point , correct? and I thought that spherical reflectors could collimate light if the light source was placed closer to the reflector than the focus(I think it may have been Dazzz or supra that said that)

why do i feel like daja vue here,,, or is it merely a reflection

I don't think so. Maybe you're thinking of a parabolic?

I think spherical reflectors come close but don't actually collimate the light.

I thought parabolic and spherical meant the same thing, only after spending a couple hours trying to find the focal point of a spherical reflector did I learn the truth...

Here's a pic I lifted and edited from here: http://www.phys.utk.edu/daunt/Astro/Overhe...Telescopes.html

Could just jump on over to the Lumenlab wiki as well.

http://www.lumenlab.com/protectedwiki/Reflectors

Spherical reflectors do have a focal length just as convex lenses have a focal length. Both suffer from spherical aberration meaning rays at the periphery don’t refract or reflect to the focal point. A parabolic reflector is designed so that the peripheral rays do reflect back to the focal point. And the convex lens has an equivalent as well, an aspheric lens.

DJ