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HMIs: What features to look for when buying

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Isabelle Landers

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I want to buy a HMI, but don't know what to look for. I can only afford to spend about $2000.00 ($3000.00 max), but don't want to buy a Chinese knock off. There are a number of used lights on ebay, but I am not certain which would be best for me. I shoot mostly indie shorts, so it is important that I be able to plug it into the wall or run it off a portable generator. From what I have seen on ebay, it seems like the most powerful light that I can afford is a 1200W. But, I am uncertain if I should get a fresnel or par light, with a magnetic or electronic ballast. I have listed a number of the options below.

Arri Par Plus w/ Electronic ballast (out of my price range unless the seller comes off their asking price)

http://cgi.ebay.com/ws/eBayISAPI.dl...313617&ssPageName=STRK:MEWAX:IT#ht_500wt_1182

Desisti 1200 Fresnel w/ mag ballast

http://cgi.ebay.com/ws/eBayISAPI.dl...954253&ssPageName=STRK:MEWAX:IT#ht_500wt_1182

LTM 1200 Par w/mag ballast

http://cgi.ebay.com/ws/eBayISAPI.dl...209106&ssPageName=STRK:MEWAX:IT#ht_500wt_1182

Arri 1200 Fresnel w/Mag ballast

http://cgi.ebay.com/ws/eBayISAPI.dl...467755&ssPageName=STRK:MEWAX:IT#ht_760wt_1167

Strand 1200 Par w/ mag ballast

http://cgi.ebay.com/ws/eBayISAPI.dl...akeTrack=true&ssPageName=VIP:watchlink:top:en

I would appreciate any input on these lights and guidance in general.

Thanks, Isabelle Landers, Gaffer
 
Isabelle
In my humble opinion it's not worth spending money on just one light, and if you do, you better get one that will last and hold its resale value.
Go with Arri, Ltm, K5600 Joker800. As they are very common and will always complement the rental package (use the same components)
Look what is most popular in your area (check the rental places to start with)
You can get an arri 1200 with magnetic balast for 2000-3000.

Just my 2cents
 
You don't want anything above a 1.2k (except maybe Arri's 1.8k, which isn't affordable, so nix that) if you plan to plug into 20amp wall sockets; 1.2k HMIs draw around 11-14amps but more when they strike. Magnetic ballasts draw more than electric ballasts while being struck but less when they run--so always strike magnetic ballasts first (then electronic ballasts, then tungsten fixtures, etc.) if you have multiple lights on one circuit.

Don't buy a desisti. The desisti ballasts are faulty and will almost always fail. Anecdotally, I've had bad luck with desisti ballasts, too, and the build quality of their HMIs is just okay while Arris are tanks.

Among electronic ballasts, Arri ballasts and Powergems are the best but quite expensive. LTM ballasts have different pin configurations (and some old lights use socapex rather than veam cables, further complicating the issue) so generally don't mix and match ballasts and heads--although this can work and I run a light of my own like this. I believe both Arri and Powergem ballasts are power factor corrected, which means they are suitable for use on sine wave inverter generators and will not introduce too much distortion into the sine wave. But they're very expensive. Cheaper electronic ballasts are not necessarily power factor corrected and are less reliable. I don't recommend them. Magnetic ballasts are much cheaper (and generally more reliable) but they can introduce flicker and the red's rolling shutter exacerbates it. But the red SHOULD be fine at safe shutter speeds (1/24, 1/30, 1/48, 1/60), though I've heard it has issues at 1/48. Magnetic ballasts also introduce very little harmonic distortion into a generator's sine wave so if you plan on using a Honda generator a magnetic ballast is a good choice so long as you stick with safe frame rates and shutter angles.

As for frensel vs. par it doesn't really matter. Fresnels are easier to use and they throw harder shadows (which can be nice for venetian blind patterns and cookies) but pars are substantially more efficient when spotted down (similar at full flood). If you need that efficiency (for day exterior fill or to send beams of light--which won't be sharp with a par and would be better with a fresnel or modified ellipsoidal--through windows) maybe get the par but the fresnel is easier to use and you won't have to switch between fragile lenses.

There are also three kinds of bulbs: par64, double-ended, and single ended. Replacement par64 bulbs are like $600+ each so avoid them, which are usually just in very old lights. (That said, they have a beautiful dichroic coating and produce awesome light.)

Long story short: LTM, etc. are good brands but I would buy what the rental houses buy: Arri, Powergems, or Joker 800s. You can get an old 1.2k magnetic ballast fresnel from Arri for under $2000 if you look around. Powergems ballasts and the Arrisun 12 are just the nicest things out there but very expensive for not that much more on return. You'll also need to buy a junior stand, which is another $300 or so.

As a gaffer, you should know this, though... The gaffer is usually the highest paid person on set because the safety of the crew and efficiency of the shoot depend on the gaffer's ability to run cable correctly and ensure lights are rigged safely. A professional gaffer should have all the skills of a DP, a key grip, and a licensed electrician. I only say this since I've been yelled at a few times for renting/buying small HMIs without what grip houses considered requisite knowledge to use them.
 
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In support of Magnetic HMI ballasts

In support of Magnetic HMI ballasts

Isabelle Landers said:
I want to buy a HMI, but don't know what to look for..... I would appreciate any input on these lights and guidance in general.
Click to expand...

Hey Isabelle,

My 2cents is that buying a used 1200W HMI light has got to one of the hardest lights to buy. Because of the constant improvement in HMI technology there are many options available and if you are not careful you can get stuck with a lemon. In head design you can choose not only between Fresnel or Par, but also the older double ended globes verses the newer single ended globes. In ballast design you have a choice between magnetic and electronic ballasts; and to complicate matters even more, you have a choice between Power Factor Corrected electronic ballasts and non-Power Factor Corrected electronic ballasts.

The basic difference in head design between a Fresnel and Par is that a Fresnel gives you less output for the wattage, but the light is crisp and you will be able to cut a clean shadow edge. A Par on the other hand will give you more output, but the light is sloppy and you will not be able to cut a clean shadow edge. The newer single ended globes put out approximately 10% more light than the older double end globes and allowed manufacturers to make a more compact head design. The newer single ended heads are smaller and lighter for that reason.

Given the type of filming you do, you may in fact be better served by an older magnetic ballast over a non-Power Factor Corrected electronic ballast. A 1.2kw non-PFC electronic ballast draws 18-19 amps ( verses the 13.5 amps of a magnetic ballast) so it will always trip the common 15 amp house circuit and will trip a 20 Amp circuit if there is something else, like a computer or light, on the same circuit. Where you can't always know what else is on the same circuit, or even if it is a 20 or 15 Amp circuit, a 1.2kw magnetic ballast drawing only 13.5 Amps is the safer bet since it can operate on a 15 amp circuit even with other things on the circuit. Non-Power Factor Corrected electronic ballasts are meant to be used on film sets where every circuit is 20 Amps and you know what is on the circuit because you are distributing the power yourself from a tie in or generator.
Since your style of shooting requires that you plug into wall outlets, you will be better served by a magnetic ballast.

But that is not the only benefit to using a magnetic ballast over a non-PFC electronic ballasts. If you don’t have access to the newest PFC electronic ballasts, the older magnetic ballasts are in fact cleaner running on portable gas generators than non-PFC electronic ballasts. As mentioned above the harmonic distortion created by non-PFC ballasts reacting poorly with the distorted power waveform of conventional AVR generators limited the number of HMIs you could power on a portable generator. The primary factors limiting the use of HMIs on portable generators has been the inefficient use of power by non-PFC electronic ballasts and the harmonic noise they throw back into the power stream. The adverse effects of this harmonic noise, can take the form of overheating and failing equipment, efficiency losses, circuit breaker trips, excessive current on the neutral wire, and instability of the generator’s voltage and frequency. For these reasons it has never been possible to operate more than a couple of 1200W HMIs on a conventional 6500W portable gas generator. The increasing use of personal computers, hard drives, and microprocessor-controlled recording equipment in production has created an unprecedented demand for clean, reliable power on set.

However, now that inverter generators, like the Honda EU6500is, do not require crystal governors to run at precisely 60Hz, magnetic ballasts offer a cost effective alternative to dirty non-PFC electronic ballasts because you can operate magnetic HMI ballasts “flicker free” on inverter generators. And as mentioned above, the smaller magnetic ballasts (575-2500W) offer the distinct advantage of being less expensive and draw less power (once they have come up to speed) than the commonly available non-PFC electronic equivalents (13.5A versus 19A for a 1.2kw.)

Of course there are downsides to using magnetic ballasts. One down side is that you are restricted to using only the safe frame rates and shutter angles. But, when you consider that every film made up to the early 1990s were made with magnetic HMI ballasts you can see that being limited to the safe frame rates is not all that restrictive. Another downside to magnetic ballasts is that you can’t load the generator to full capacity because you must leave “head room” for their higher front end striking load. When choosing HMIs to run off portable generators, bear in mind that magnetic ballasts draw more current during the striking phase and then they “settle down” and require less power to maintain the HMI Arc. By contrast, an electronic ballasts “ramps up”. That is, its’ current draw gradually builds until it “tops off.”

While older HMIs with magnetic ballasts are less expensive to purchase or rent, Power Factor Correction (PFC) makes the newest electronic ballasts worth the extra money when it comes to lighting with portable generators. The substantial reduction in line noise that results from using power factor corrected ballasts on the nearly pure power waveform of an inverter generator creates a new math when it comes to calculating the load you can put on a generator. In the past we had to de-rate portable gas generators because of the inherent short comings of conventional generators with AVR and Frequency governing systems when dealing with non-PFC electronic ballasts. The harmonic distortion created by non-PFC ballasts reacting poorly with the distorted power waveform of conventional AVR generators limited the number of HMIs you could power on a portable generator to 75% of their rated capacity (4200Watts on a 6500W Generator). But now, where inverter generators have virtually no inherent harmonic distortion or sub-transient impedance and power factor correction (PFC) is available in small HMI ballasts, this conventional wisdom regarding portable gas generators no longer holds true. Where before you could not operate more than a couple 1200W HMIs with non-PFC electronic ballasts on a conventional generator because of the consequent harmonic distortion, now according to the new math of low line noise, you can load an inverter generator to capacity. And if the generator is one of our modified Honda EU6500is inverter generators, you will be able to run a continuous load of up to 7500W as long as your HMI and Kino ballasts are Power Factor Corrected.

I would suggest you read the article I wrote for our company newsletter (especially the section titled “New Life to Old Ballasts”) on the use of portable generators in motion picture lighting. In it I cover some of the basic electrical engineering principles behind poor Power Factor, the harmonic distortion it can generate, and how it can adversely affect generators. The article is available at http://www.screenlightandgrip.com/html/emailnewsletter_generators.html.

As far as used HMIs that are available for sale I would caution you against buying a system with Lightmaker ballast. As mentioned above Lightmaker ballasts were the first generation of non-PFC electronic ballasts made and were nicknamed the “Troublemaker” ballasts because of the problems they caused. While the Power Gem & Arri ballasts are of a later generation, the used ones out there will likely be non-Power Factor Corrected. Which is why you may be better served by a magnetic ballast for your type of filming.

Guy Holt, Gaffer, ScreenLight & Grip , Boston
 
Matt W. said:
I believe both Arri and Powergem ballasts are power factor corrected, which means they are suitable for use on sine wave inverter generators and will not introduce too much distortion into the sine wave. But they're very expensive. Cheaper electronic ballasts are not necessarily power factor corrected and are less reliable. I don't recommend them.
Click to expand...

Matt's point regarding Arri & Powergem ballasts requires some clarification. Finally, after years of dragging their feet Arri & Powergems are finally putting PFC in 1200W ballasts. That was not the case until very recently. Where Power Factor Correction (PFC) is very new in 1200W HMIs, it is highly unlikely you will find it in a used ballast – even a Power Gems or Arri ballast. Since Power Factor Correction (PFC) is not mandated in this country, as it is in Europe for any electrical device that draws more than 75W, most Americans are pretty much ignorant of Power Factor and effect that poor Power Factor can have on a distribution system. However, any film technician familiar with large HMI heads will be quite familiar with Power Factor and Power Factor Correction (PFC.) That is because after a false start back in the 90s, all major manufacturers now include PFC circuitry in HMI ballasts in the 6-18kw range. They do so by necessity. The early line of Lightmaker electronic ballasts were nick named by film electricians “Troublemaker” ballasts because they were not Power Factor Corrected and proved that PFC circuitry was absolutely necessary in large ballasts to reduce heat and returns on the neutral, and to increase ballast reliability (beware, some are still kicking around ebay). But, because of the added cost, weight, and complexity of PFC circuitry, ballast manufacturers in the US still only offer PFC circuitry as an option in medium-sized 2.5-4kw ballasts. And, until very recently manufacturers did not offer PFC circuitry in HMI ballasts smaller than 2.5kw in the US (in the EU PFC circuitry in mandatory in all HMI ballasts sold.)

Part of the reason was that PFC circuitry did not offer a huge advantage when plugging into house power. A typical 1200W Power Factor Corrected electronic HMI ballast will draw 11 Amps at 120 Volts verses the 19 Amp draw of a non-PFC electronic ballast. While not a huge advantage when plugging into house power, the added efficiency of a PFC 1200 ballast can make a huge difference when powering a lighting package off of a portable generator. For example, when you consider that a Kino Flo Parabeam 400 draws only 2 amps, the 8 Amp difference between using a PFC 1200W electronic ballast and standard non-PFC 1200W electronic ballast, can mean the difference between running four additional Parabeam 400s on a portable generator or not – I think you would have to agree that is a major boost in production capability and pertinent to any one using a portable generator as their principle source of set power.

Except for one notable exception, when manufacturers do offer PFC circuitry in smaller ballasts it is at a premium, adding as much as a $1000 to the cost of a 1200W ballast for instance. But where PFC is still very new to smaller heads, it is still the case that almost every 575 - 1200 W electronic ballast that you will find in a rental house or for sale used in North America will be a non-PFC electronic ballast. For a detailed explanation of PFC see my post "What is Power Factor Correction in HMIs" at http://reduser.net/forum/showthread.php?t=40275

Guy Holt, Gaffer, ScreenLight & Grip , Boston
 
Guy Bryan Holt said:
As far as used HMIs that are available for sale I would caution you against buying a system with Lightmaker ballast. As mentioned above Lightmaker ballasts were the first generation of non-PFC electronic ballasts made and were nicknamed the “Troublemaker” ballasts because of the problems they caused. While the Power Gem & Arri ballasts are of a later generation, the used ones out there will likely be non-Power Factor Corrected. Which is why you may be better served by a magnetic ballast for your type of filming.
Click to expand...

Thanks everyone for you helpful suggestions. I think I will take Guy's advice and hold out for an Arri or LTM 1200W Par with a compact magnetic ballast. While I don't begrudge anyone the right to make a living, I have personal issues with Chinese knock offs which amount to intellectual property theft and patent violation. Besides, I understand the build quality of the Chinese knock offs is not good and service is not readily available in this part of the country. What's the point of spending $3000.00 if I can't get it fixed.

Isabelle Landers, Gaffer, Nashua, NH
 
Thanks for your comments. This is always a very interesting subject to me as I have been interested in quality, what it means and the myth that quality is only available in certain parts of the world. If that were true then Japan would never have evolved into what it is today which is not the same perception of the Japan of 40 years ago. China is on that same trajectory.

Cool Lights has many happy customers on this site who will tell you they have never been left in the lurch for service if there was an issue and they told us about it. We simply execute in China with contract/OEM manufacturers, as this is where we can make it happen affordably and that's what our customers want. Cool Lights is not a trading company and we don't sell the same products as "dealers" of generic Chinese equipment do. All of our equipment is either of our own design or has our own signature improvements over what others sell. As far as quality goes, we are extremely happy with the reliability of what we sell and we do warrant everything we sell with the same kinds of warranties as other competitors do. Sure we have issues occasionally, who doesn't with new products. But we stand behind them and they just get better and better.

Product reliability is really a maturity that is born of pride of work, experience and revisions, not the country where something is made. Those attributes can be applied anywhere in the world. Much of what people complain about in products that aren't reliable can be boiled down to a combination of any or all of the following: issues surrounding laziness, dishonesty, ignorance of customer expectations, lack of thoroughness, bad supervision, lack of revisions to fix issues or perhaps not a well-thought out design--which could literally come out of any part of the world, not just Asia. Nothing is completely perfect and certainly not on generation one so you learn if you want to improve your position vis-a-vi other competitors.

If there are products that are substandard coming out of China, that is just a lack of experience or understanding of what quality is, being isolated from end customers and their comments, and in general, ignorance about what other markets expect (which by the way, is defined differently in different parts of the world). That can easily be fixed with supervision, education and exposure to the end customer, as education and exposure to new ideas can also fix generalizations and prejudices, for those so inclined. I personally feel that generalizations and prejudice are pretty dreary so I avoid them because those all tend to become your reality.

By the way, did you know that many of the subsystems used in extremely complex equipment like cameras are coming from China now? Computer motherboards too. That's right--Taiwan and Japan are the brains of Asia and China is pretty much the muscle these days, executing the manufacturing for well known factories. Its all anecdotal where something is really made and you cannot ultimately know that as its normally considered proprietary. If for no other reason than that competitors would try to run with the information and stir up all kinds of trouble. So they can do cameras or motherboards in China but they can't do lighting?

We do it the right way and that's my reality (somewhat enlightened since I've been over here in China going on 4 years now). No matter where you make something, its all about careful design, planning, listening, knowing what market expectations are, revisions as necessary and above all, supervision. That's how you get to maturity and quality. I am after all, not living over here for the culinary experience alone.
 
A vote for Coollights

A vote for Coollights

I have to chime in here and give Richard and Coollights a plug. Over the last three years I have purchased several Flo and Fresnel lights from Coollights and remain happy with every one. His CDM fresnels (I have two 150's and one 70) are terrific and have been very reliable. And, if you check out the pricing, you'll notice they are a fraction of what an Arri HMI would cost. I am NOT knocking Arri!! It is just that I can't justify the cost of an Arri HMI in the indie film work I do and don't really need the top shelf pro-level build and reliability that I am sure they offer.

The specific features I like about the Coollight CDM fresnels are that they are daylight balanced and draw a fraction of what equivalent tungsten lights draw. They also run cool. I can show up to shoot in a small apartment and can make use of available natural light, not overwhelm the talent with heat, and not blow circuits, even when I want to throw large amounts of light out. Just feels like a win to me.
 
Thanks for your comments. Can't believe its been 3 years Terry. Now we just have to figure out how to put LEDs in those fresnels, seems that's what people want for the future.
 
Richard Andrewski said:
Thanks for your comments. Can't believe its been 3 years Terry. Now we just have to figure out how to put LEDs in those fresnels, seems that's what people want for the future.
Click to expand...

Yeah. I saw the fresnel-like "Sola" product line from Litepanels at NAB. Looks pretty interesting but still relatively expensive.
 
Richard Andrewski said:
By the way, did you know that many of the subsystems used in extremely complex equipment like cameras are coming from China now? Computer motherboards too. That's right--Taiwan and Japan are the brains of Asia and China is pretty much the muscle these days, executing the manufacturing for well known factories. Its all anecdotal where something is really made and you cannot ultimately know that as its normally considered proprietary. If for no other reason than that competitors would try to run with the information and stir up all kinds of trouble. So they can do cameras or motherboards in China but they can't do lighting.
Click to expand...

Apparently they can't do lighting because I have seen nothing but knock offs from Chinese companies. And bad knock offs at that. Even your Par design still uses the snap in lens design that Arri and LTM have eliminated because it was cumbersome and impractical. I have worked with Metal Halide fixtures and find the color rendition suspect and the whole concept impractical for production - I can't wait 5 minutes to restrike a light.

The simple reality is that there are at least four Arri/LTM dealers within an hours drive of me, that can service the light if it has a problem. There is no Cool Lights dealer that I am aware of in the entire northeast. At the outset I said I was not interested in Chinese knock offs. These are just a few of the reasons. I think I will stick with a used Arri or LTM par. Thank You

Isabelle Landers, Gaffer, Nashua, NH
 
Isabelle,

Back to your original question, try to get a least one spare head cable. As I am sure you know, 99% of problems with HMIs can be traced to a bad head cable. When buying used, often the head cables have been abused, run over with c stand carts, badly coiled, just plain beaten up. Having a spare just to trouble shoot when you do have a problem is pretty important.

Nick
 
Oh, also, Desistsi makes really excellent stuff. I have a bunch of HMIs of thiers ranging from 575-4k. I have used Desisti stuff on long jibs in bad weather. It's bullet proof. The heads are made out of SS. Plus Desisti thinks about how stuff is going to go on a truck or a cart, they are squareish instead of barrell shaped so they stack and sit well.

Nick
 
One more thing to consider is that depending on how old the HMI unit is, finding the right globes for it might be tough. You might want to look into it and make sure you can readily find replacement globes when you need them for the specific unit.
 
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