Is Metal Halide the same as HMI?
 

Title says it all. I'm letting my obsessive/compulsive nature run wild again and I've decide I want to know everything I can about the technical side of lighting.

I'm finding companies that make pro-grade metal halide bulbs that have all different color temperatures with excellent cri numbers.

As an example. 4000k with 94cri in 250w... Thoughts?

No, they are different.

HMI's are alot more efficient than MH, I believe.

I don't see why you couldn't use MH lights, as long as you take the colour temperature into consideration.

One thing... Metal Halide ballasts are NOISY! They are commonly used for overhead lighting in warehouses and megastores (like Home Depot), and in streetlights. In a quiet area, you can hear them humming from a relatively long distance.

Matt...

Where are you finding these lights? Might be worth looking at.

Be aware that any arc light generates a heck of a lot of UV and some sort of effective UV filter will be needed to protect the talent and crew.

An extreme example is an arc welder. Same principal.

I once got a bad sunburn when welding steel as a teenager, not knowing any better. I wore the helmet and gloves, but no shirt. Wondered where I got the odd sunburn from until I realized it was where my skin was exposed to the arc!!

Lesson learned.

Dean Sensui
Base Two Productions.

Dean, I've just been festering around for info on the net as I usually do.

I'm one of those obsessive compulsive types and the whole fluorescent thing is what started this for me. I was looking at the Kino and Lowel fluorescent kits and I haven't been able to figure out how they arrive at the super high prices. With fresnels and most openface lights I see a reasonable price/construction relationship... personally I think the LTM, Arri, Mole fresnels are a pretty good deal for what you get. And I think the Lowel openface lights are a good deal for the price and what you get there too... then we come to the fluorescents... what the heck is up with those? Over $1k w/o bulbs? I don't get it. No lens, no nothing... just a softbox by nature...

As it turns out good photo quality fluorescent bulbs can be had at less then $30 each.

Then some people get their eyes glazed over when they read "ballasts" and tech stuff... the reason CHEAP homeowner grade fluorescent lighting flickers is because it operates at 60hz... get a Super-Tek Electronic ballast and it operates at 60*Khz*... so NO flicker... one of those is less then a hundred bucks and often less then $75...

So the cost for ballast and case is what? $150? And then w/o bulbs they sell for $1K-$1,500? Seems kind of crazy to me...

DYLAN, the above ramblings leads me to the search for HMI info. I've been dissapointed at how little I've been able to find about HMI... I've found basically NONE... but when I search for it I always end up finding Metal Halide... so I thought they could be related.

With BOTH of these topics I want to tell you that it's not too hard to find bulbs in SUPER high CRI values and in almost ANY color temperature you want...

DYLAN has effectively shut down my interest in Metal Halide... THANK YOU for that! I have a bad habit of wasting my own time mindlessly determined to answer questions... I've seen exactly what you spoke of for myself... so Metal Halide is over.... although I should mention that you can get 250w Metal Halide bulbs with 4000k color and 94-96 CRI... so that should be a damn good bulb.

From what I understand a CRI of 100 is perfect and the color temp we USUALLY want is around 3200k... isn't that correct? I've also read that noon day sun is 5600k... so I'm assuming that we like the 3200k for it's slightly warming character? But wait! There's more! I've read that acceptable photo light starts in the mid to high 80's on cri... so anything in the 90's should be good and high 90's should be basically perfect. No?

You guys are great! Please offer some input on the fluorescent thread if you can...

Matt,

If your obsessive/compulsive nature has taken over and you've <<decide [you] want to know everything [you] can about the technical side of lighting>> ... then here's a brain-teaser for you.

Not long ago, I saw a highway crew here in Japan working at night using this one, amazingly brilliant light to see what they were doing. I've been wondering what type of light that was. It looked perfect for lighting night shots and getting a true moonlight effect.

Strange thing was, it was floating. No kidding. It looked like a chinese lantern made of some type of fabric, inflated like a blimp. It was moored with a couple of thin ropes or cables. The light-source was obviously centered inside and didn't flicker...and it cast this ultra bright bluish moonlight-blue hue in all directions. It was the brightest light I've ever seen.

It looked like the whole thing could be collapsed down to fit easily in the back of an SUV, but could light an entire set practically.

Anyone have any idea what that is?

It was godzilla

Zac

HMI is one of Osram's versions of metal halide lamps. Osram claims higher efficiency because of higher working temps (because of better sealings) and "hot restrike" properties. CRI is basically like all MH lamps.

So HMI IS metal halide? Which is it?

John, that sounds pretty wild. I have no clue what that could have been. I know the gas-arc lights are freaky bright. Unbelievable in person... but a blimp? Maybe a new product called the Tungstendenburg.

Andre... gimme' more! Do you have an internet source I can go to in order to find a graph of the emission characteristics? I found them on Kino Flo's web site for their fluorescents, but I haven't seen any graphs on tungsten...

The other thing to keep in mind here is that I will STILL get tungsten fresnels and maybe an openface, but since softlights are usually the most costly I'm doing this in an attempt to get the best possible product at the most reasonable cost.

I figure a good light kit contains at least two softlights and I can go traditional from there... also I like the idea of cutting heat wherever I can...

<<<-- Originally posted by Zac Stein : It was godzilla

Zac -->>>

LOL!


Matt, although Andre is right, he's not saying HMI is the same as MH.

Take a look at the bulbs. (using Ebay as a picture source)
HMI
Metal Halide

There may be hope for metal halides soon. Electonic ballasts have been made for them, and will probably hit the market soon. However, the bulbs are considerably larger, meaning a bigger light overall, so I don't expect to see any MH film/video lights anytime soon, if ever.

If you are a DIY guy, halides might be the best value for the dollar. You can get a 1000w bulb and ballast for less than $150. Just put the ballast in a different room from where you are shooting.

Just to let you know. I've already found electronic ballasts for metal halide lights at a reasonable cost. Also you can get metal halide bulbs down to 200w and lower... I don't forsee a use for too many 1k metal halide bulbs in my future. The wacky size of that 1k is because it's a 1k.

Also after researching this all morning I've found ballasts that are supposedly totally silent. Eventually I'll know if those manufacturers are full of crap or not... but I'd expect they would be begging for negative PR if they claim the ballast to be totally silent when in fact it was noisy.

At this point I still expect to go with standard tungsten fresnels... I'll see how the fluorescent experiment goes and then decide on this deal.

Thanks for all the help guys.

I want a couple HMI's, annybody suggest a decent one to look at, nothing outrageously priced please.

Zac

Matt, see http://www.soluxtli.com/edu9.htm for emission spectra.

Andre, I was excited to see that you could help me out on this, but when I went to your link I see that those graphs are lacking any source. There is a pretty big difference from one "daylight" fluorescent to another... using a graph to support facts without ANY explanation of where they actually obtained the numbers is worthless. It's too ambiguous... I'm sure that to some extent the general idea is the same but without reference it doesn't count.

Matt, I know there are differences. If you really want details I think you will need to contact manufacturers unless you have a spectrometer available. What are yr applications? My company (Barco) quite often needs detailed emission spectra for optimal color splitting filter design in projectors, but I don't think the very precise emission spectra for video/photo lighting are so crucial once you get 80+ CRI values specified.

A quick visit to this site: http://www.laserovashow.sk/balon3.htm should answer all your questions about the aforementioned "tungstendenberg".

also visit http://www.lightsup.net/film-set-new.html for more film related applications of this type of lighting

Matt, could you please post the links to the metal halide electronic ballasts? I'm curious about them. I didn't think they were available to regular joes yet.

I keep forgetting that you are looking for less lighting, rather than more. My fault. I believe you can get MH bulbs down to 75 or 90 watts actually. Look for halides for the aquarium industry.

Dylan, I'm sorry but I'm checking this thread before I go to bed... It's midnight for me right now.

I found everything I found by going to google.com and just typing in ideas in the search box.

If you type in electronic ballast you will be linked to several outlets to pick up a metal halide ballast... otherwise go to sylvania.com and go to electronic ballast and you'll have a selection of metal halide ballasts...

The other ballast manufacturers have similar products, but it's clear Sylvania is on the charge to dominate where they can. Motorola use to be big with ballasts, now "they" are sylvania.

HMI
 

Check out Osram, they sell everything but it is expensive. you can find the bulbs you are talking about in LCD projectors and such. When mine starts to get a little weak, I pull it and store ot in a safe place to use later as a backup or for something else. I have a power supply that will run them as it was made for a medical HMI light source. :)

Matt,

Call CineServices downtown. They can probably answer your questions. If you need to see it, and it's not too much trouble to set it up, you can go down there and they'll show it to you and turn it on and show you how it works.

Bad Dog Productions, in Kirkwood, will do the same. But for both of them make sure you ask for a good time to come down in case they're busy.

Thanks Rob and Kevin... I've been "marathoning" my lighting knowledge on the internet and I've got all my questions answered... now I just need to decide on what I will buy, what I will build, and how I will build it...

For my purposes it looks like two mole fresnels and two tungsten balanced fluorescents... and I expect to build the fluorescents, but maybe not... the Kino Diva 200 and 400 are actually pretty reasonable for what you get. To build something similar to that would only save you $200-$300 and wouldn't look as professional... Also with ANY of the cf fluorescents you can choose between daylight and tungsten by using different cf tubes... so you can mix a color matched soft-light with a fresnel... and then later on use one or two soft-light daylights for daytime/moonlight effects (with gels)...

I look forward to talking with you Rob, and thanks for the tips on local producers.

<<<-- Originally posted by Andre De Clercq : HMI is one of Osram's versions of metal halide lamps. Osram claims higher efficiency because of higher working temps (because of better sealings) and "hot restrike" properties. CRI is basically like all MH lamps. -->>>

Sorry for being late, but the above statement is not true. CRI for HMI is different than typical MH and that's the whole point. Osram lists CRI's above 90 for all their HMI lamps and there's a big difference between 70-75 and 90-95.