HMI for use with Video?
 

Just wondering if anyone can tell me whether the flicker that film picks up from HMI lights with mag ballsts also shows up on 24p video, and if so, how bad is it and what is the best way to deal with it? Also, do the flicker free ballasts introduce a lot of noise? My understanding is that they can cause the globes to make a high pitched sound.

Thanks,
Matt

I've used a number of HMI's up to 2k Hemi's.
Haven't seen any flicker- haven't shot 24p though. It shouldn't be a problem, since they are also used on film shoots without issue.

Jeff Patnaude

Thanks, I have never used them, but it is my understanding that the shutter speed has to be set just right in order to avoid the flicker when using film. I am wondering how this translates when shooting 24p video since I want to shoot at 48fps.

proof in pudding
 

those mag ballast can be awesome or terrible.

avoid if possible mag ballasts

if itt is good then forget all I said.
per pref is mole digi and www.k5600.com


R

Building Your Own Metal Halide (Low Cost HMI) Fresnel Part II
 

I just posted the Part II of my article on building your own metal halide fresnel on my website. This one gets down into the actual mechanics of the conversion.

http://www.coollights.biz/wordpress/archives/33

I clearly showed how it can be done for less than $500 if you're careful about picking the right parts and find a used fresnel for the right price. I did mine for less than $200, but I'm based in China right now so I have a bit of an advantage ;-).

In part I, we talked about the theory behind all this:

http://www.coollights.biz/wordpress/archives/31

Please follow all electrical safety and metal halide bulb safety guidelines suggested there.

I'm looking forward to buying some parts from you. I know you're working on completed fixtures, which could take some time, but do you have a timeframe in which you might be selling ballasts and bulbs?

I'd seen the lumenlab setup mentioned on another forum, but because of bulb size, I'm interested in the smaller double ended bulbs. Do you have a line on 400w or 1200w inexpensive bulbs similar to the 150w you show in the article?

I hope for August timeframe but manufacturing tends to have a way of always taking a bit longer than you think.

Yes of course. Everyone feels this way too I think including me. It's just a matter of convenience vs. complexity. The smaller bulbs entail a bit more work. The screw in kind are a bit easier to work with. When doing some of these DIY solutions you're always balancing ease for people to complete the project and cost with something that is ideal.

Yes I think we'll have some bulbs in the 150w, 575w and 1200w size all single ended. Probably either 5200K or 6000K because 5600K is so darned hard to get.

Double ended don't make for as great of a fixture in my opinion--especially on a Par fixture. Most people are probably thinking they'll need the 575w and 1200w most but you'd be surprised how much light comes out of the 150w bulbs. Indoors, a 150w CMH fresnel is a great portable solution.

HMI has many names
 

I'm trying to find the most agreed answer for what HMI stands for. I've heard lots of different answers (similar to what ADR stands for). Some include:
Halogen Metal Iodine
Mercury medium-arc Iodine
Hydrargyrum medium-arc Iodine

What's the name most people go by?

Most people go by HMI, but you can add "metal halide" or "HID" to that list too as it is a member of that family. I wrote a couple of articles recently and am writing the third part right now:

http://www.coollights.biz/wordpress/archives/31

and

http://www.coollights.biz/wordpress/archives/33

Here's an excerpt from Part 1 dealing with your question:

To start with, did you know that HMI (which stands for “Hydrargyrum Medium-Arc Iodide” Hydrargyrum is the latin for “mercury“) is really a tradename of the Osram Corporation and not referring to some proprietary technology? Nor does it refer to the ballast driving the bulbs either–I’ll talk more about the ballast in a bit though. Also, did you also know that other manufacturers make similar products under different names? Philips has “MSR.” GE has “ConstantColor.” And so on…

Thanks for the clarification! It was kind of embarrassing when I was talking to someone starting out in lighting, and I tested them on what a HMI stood for. They didn't know, I told them "Halogen Metal Iodine" because that's what my LA gaffer told me. Then they looked it up online, and told me I was wrong. Thanks for clearing it up. Hopefully others can read your article and be more knowledgable.