Hard-light retrofit: automotive 35w Xenon

T

Trey T

Active member
Hard-light retrofit: automotive 35w Xenon

specs are:
-35w bulb
-D2S/D2R base
-3200lumens
-4300K

other thread I asked about other types of high intensity discharge lighting such as HMI, but since I have a bunch of automotive xenon(bulbs and ballast) hanging around the garage, I thought maybe I can put it to a good use for a retrofitting onto a housing like this.

-will it be enough light to shine the single subject from about 50' away?
-will I run into flickering of ballast?

I have tested the ballast awhile back and the voltage is constant after it's fired. What is great about the automotive HID is that I dont have to wait for cooling after being fired, unlike other metal halide I've seen.
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anyone know the search key to find a used light like the above link?
 
We've experimented with those before. I doubt it will be all that powerful in a fresnel and is unlikely to make a beam that will shine brightly for 50 feet. Also you'll need to use a 3/4 minus green filter (or so) as the green spike is pretty bad in those types of light.
 
did y'all use OEM ballast or generic ballast? the green spike, do you think that happens in general for all xenon setup or is it the ballast?

how about two bulbs w/ a good reflector? what am I looking at as far as lighting design?

any comments are welcome.
 
I guess you would classify it as an oem ballast but I didn't think about it much so not sure. I don't think the ballast is much of an issue and didn't see flicker as a problem. The color rendering of the 35w bulbs is the issue. Every xenon we tried had the overly green output as well as regular 35w metal halide bulbs. Its apparently not easy to build a bulb that size with a good CRI. We even have considered just building in a minus green dichroic filter into the fixture just behind the lens but were hoping for a better bulb though. Wanted to use them in our 150w tungsten fixture to make a CDM 35 fixture for our line.

If I were doing it for a product, I would skip the ones in the 4000K to 5000K range and get a 6000K one to match other hmi type lighting as well as far as color temperature is concerned.

If you built a fresnel with two of them, I'm sure it would work but it wouldn't have all the regular behaviors of a normal fresnel. You'd likely get double shadows and while it may not be a concern for most of what you want to do with the light, it wouldn't work for things like rendering a cookie pattern on the wall in any intelligible fashion. The double shadows would kill it...
 
Richard,

I'm glad you go through all this grief so we don't have to. DIY Filmgear is an expensive "money saving" hobby!

-J
 
"OEM" bulbs are generally made by two companies, phillips and osram( and GE too but no mass prodction). the two brands retain a very good CRI, several yrs b4 it even gain it's color temperature but lose it's lumens. philips and osram also make 5000K bulbs to "match" used 4300K bulbs. 4300k and 5000k is the most popular bc it's bright white and has maximum lumens.

for ballast, the three most popular names are Denso, Bosch, and Matsushi*a. Osram have their own game, but came after. it's design to last about the life of a vehicle but thats not always the case. I have a denso set in my car that is dated over a decade and works flawlessly.

now I dont know what you used but I hope you use OEM product instead of cheap chinese HIDs. I will do some testing soon to let everyone know but I already think this whole project is NOT going anywhere bc ive thought about it. Who knows, I might have a change of plan.

as far as shadow and the way it is filmed, it doesnt matter. we only care about the subject being lit.
 
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> as far as shadow and the way it is filmed, it doesnt matter.
> we only care about the subject being lit

That gives me pause for cause because a good DP lights with shadows...
 
shadow and non-shadow, that is subjective. let's just say that the subject and the area will be lit or else we'll get into endless discussion. :)
 
For purposes of a one off DIY product I can certainly understand doing something special like that. For our purposes of creating a general purpose Cool Lights product, we would stick to a more traditional design of fresnel or even perhaps a miniature ellipsoidal with convex lens. Being able to get one shadow is very important for normal and general purpose use or what people would be expecting of such a light if they heard the terms "fresnel" or "ellipsoidal" used in marketing it.

I did use the cheaper chinese HID versions in my tests up till now, so the idea of trying an Osram or other name brand certainly has some merit if the output is better and also gives a better CRI--and of course also that it doesn't jack the price up so much that it wouldn't work for our pricing models.
 
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