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1st time HMI user
I’ve posted on this forum before and gotten fantastic advice. So…thanks for that.
I’m going to be shooting in a school (again). This will include single and two-shot interviews, general classroom footage, hallway footage of kids walking. I’m thinking of venturing into the world of HMI lighting for the first time and renting a ARRI COMPACT FRESNEL 1200W HMI. I’ve been using Arri tungsten lighting for a while and I’m comfortable with it. Will there be a big learning curve going to HMI?
My overall strategy was to use whatever daylight I could find, and supplement with diffused or bounced light from the HMI. I also have a few tungsten lights with daylight gels I can throw in for extra/fill. For the classroom, I thought I’d bounce the HMI off the ceiling.
Any thoughts on this strategy.
Thanks again!
Dan S.
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54 Replies
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Bouncing lights off the ceiling works ONLY to ambient fill. Overheads almost always make a lousy key except for special circumstances. In this case, to make the classroom look pleasant with good light on the participants’ faces, you will do much better if you can direct lights through windows. Use the overhead bounce only as fill.
Remember how light falls off rapidly as the distance increases.
Rick Wise
director of photography
San Francisco Bay Area
part-time instructor lighting/camera
Academy of Art University/Film and Video (grad school)
https://www.RickWiseDP.com -
Thanks, Rick.
So what you’re saying is use the HMI to increase the window light and use as key? Would a 1.2k HMI have enough punch to give a nice key to the room from outside in a typical size classroom? I know this depends on a lot–size of windows, intensity and direction of sun, etc.
Dan S.
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There’s not too much of a learning curve… just remember that compared to your tungsten instruments, aside from the color balance that HMI is going to have a lot more punch… the 1200w HMI is going to be about four or five times brighter than a 1200w tungsten instrument. Which is a good thing.
Another thing that will make it a bit easier is the fact that it is a fresnel. So many HMIs are PAR instruments, and you’ll sometimes find yourself constantly swapping out lenses as you tweak your lighting (often HOT lenses), but with the fresnel it’s easy breezy… just turn a knob to focus, just like any tungsten fresnel. I love the Arri Compact… it’s a great head.
Personally, to light a classroom predominantly (and easily) with a single 1200 as my main source I’d do it in one of two ways… with method one, I’d put a white 4×4 bounce card fairly high on a stand (and tilted at about 45°) on the same side as the windows. I’d then put the HMI head down low and near it… I’d probably just put the head directly onto the turtle base of a regular C-stand (the base of a C-stand has a receiver exactly the same size as a Junior stand, so the head will fit… I do this all the time). I’d then tilt the head very upward to blast into the bounce card. That’d give a nice even light. Method two… I’d put the HMI on a high stand on the same side as the windows (high and to the rear of the scene), and use it to hit a white bounce card on the other side of the scene. In that method, your single HMI will perform double duty… you’ll get general soft illumination from the bounce card, and you can steal a bit of “stray light” (fiddle with the barndoors) directly from the instrument which will give you some hard “splashes” across the scene for some side/back lighting. I do this a lot and it works well. Now, it is hard to envision something exactly in your head and have it turn out that way precisely, but it’s a good “Let’s throw it up and see if it looks interesting” method, which it often is.
T2
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Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com
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Daniel,
Also be SURE to talk to the rental house about the light’s “hot strike” issues, if any.
If you turn off the light, you may have to wait a specific amount of time before you re-strike to protect the VERY hot and VERY expensive lamp.
Paying for a new lamp for an HMI that got plugged into a circuit on an easily accessible light switch is something you’ll remember for a long time. : )
Have fun.
“Before speaking out ask yourself whether your words are true, whether they are respectful and whether they are needed in our civil discussions.”-Justice O’Conner
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Thanks, Todd.
I’m including a diagram of methods 1 and 2 to see if I got it right, along with some questions. (I hope I upload properly)Questions for Method 1:
1. How hot does the 1.2k HMI get? They’re High School kids, but do I need to worry about them getting burned?
2. Do you think the single light, bounced as shown, will give a wide enough light for the classroom to give the feeling of window key?
3. Also, do you think most schools will have enough electricty to supply the 1.2? I’m asssuming that a 1.2 HMI draws the same electricity as a 1.2 Tungsten (which isn’t too bad).
4. Would it be better to have the light/card closer to the front of the class to have a little less of a side light, and a little more fronts of faces lit? I assume I’ll be shooting away from windows or from the front of the class facing the back.Dan S.
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Here’s my take on Method 2 with some questions.
Questions for Method 2:
1. Is this what you had in mind?
2. Will the 12k fresnel focus enough across the room to get significant bounce off of a 4×4?
3. Would the Key be the bounce across the room, and if so, would I want to shoot from the front of he room?
4. Considering I’ll have limited time for setup and testing, would you say Method 1 is a bit safer/easier?Dan S.
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Hey Daniel…
Yes, the diagrams of your two methods are pretty much what I had in mind. With the “Method 1” I probably wouldn’t put the instrument and bounce card exactly where you did, but would most likely let it drift a fair bit either backward or forward in the room. But it’s easy enough to play with to see what you like.
I wouldn’t say 1 vs. 2 would be easier, safer, or better. Just different. They both use exactly the same equipment, just in different ways and will give different results. It’s just whichever looks better to you.
Ideally it’d be nice if you had more firepower to work with, but even with that single instrument it’s a good starting point to develop your lighting plot. I’ll note that a couple of times in your posts and diagrams you refer to it as a 12K. It’s not… it’s a 1.2K (or 1200w). A 12K is a different beast altogether… and I do mean beast.
You should not have any power problems with the 1200w unless someone is running something very wattage-intensive on the same circuit. Most commercial locations will have 20 amp breakers, but even a 15 amp breaker (more common in a home) is sufficient for that instrument, unless there is a big load already on it. We use our 1200w HMIs in residential locations all the time.
Remember, the formula is watts / volts = amps (or amps X volts = watts)… so a 1200w instrument on a 110v circuit will require about 11 amps (1200 / 110 = 10.9). HMIs do have a bit of a power surge or “spike” right when they strike, so it’s best not to cut it too close.
Worrying about people getting burned? Well, yes… but no more so than with any other hot lighting instrument. Worry about it the same as if it were a tungsten instrument. An HMI is usually going to run a little cooler than the same-wattage tungsten instrument (and an Arri Compact is one of the cooler instruments)… but of course they still get quite hot. Take normal precautions.
And yes, I’d position the bounce card so it illuminates faces, not a harsh 90° side lighting. More like a 45°-ish angle.
Mention was made of hot-restriking. True, some HMIs (usually older ones) won’t hot restrike, and you have to let them cool down first (one of our older/smaller HMI heads/ballasts is a non hot restrike…. and yeah it’s a pain in the rear because people are always forgetting and turning it off or unplugging it). But most modern HMIs will restrike (the Arri Compact and the globe that’s usually in it will) so it’s probably not an issue.
T2
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Todd Terry
Creative Director
Fantastic Plastic Entertainment, Inc.
fantasticplastic.com
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Wow! Fantastic advice! Can I take a class with you???
Dan S.
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And yes, the 12k was a typo!
Dan S.
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Okay one more question: Renting two 1.2K’s is not a whole lot more expensive. Would that be better in the “firepower” department?
Dan S.
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