Cdm-t Vs Hqi-t

This is the information that I have gathered about hqi-t and cdm-t bulbs, is it correct?

The hqi-t have a clear glass tube that makes the arc clearly visible. The arc in such bulb is not uniform neither in brightness or position. It is brighter near the ends and the arc will not be straight but bend in some way (usually upwards if positioned horizontaly).

The cdm-t have some sort of cheramic tube for the arc and the arc itself can not be seen. It can therefore not be used in a spherical reflector.

Do the cdm-t generate a uniform lumination from the ceramic tube or is it like the hqi-t?
The reason I ask is that I'm having problems with positioning my hqi-t in a elliptical reflector due to the non uniform illumination and wonder if switching to a cdm-t will solve it.


2004-07-25 10:06 pm
could you tell us the rear fresnell focal and placemnt from the bulb? also could you tell us the f1 and f2 of your eliptical reflector?
tell us the eliptical reflectors diameter as well.

what is the light distribution problem? (dim corners?, asimetrical brigtness?...)