Chris Schlaghecke
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Posts posted by Chris Schlaghecke
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The color of Fluorescents will very depending on temperature. When they get hot they tend to have more of a green spike and I believe more blue. This is why they recommend not putting gels inside of the barndoors on kinos because it can cause them to get hotter which will shift the color temperature. Also, if you underdrive the tubes (ex. run 4ft bulbs in 2ft mode) they will look more magenta. I would also assume that there would be some differences depending on the temperature of the location, etc..
One thing that I have both been told and observed is that the human eye(atleast mine) tends to be more sensative to differences in the magenta/green level than film seems to be. I have been on shoots where there was a noticable inbalance but it looked fine on the resulting film even without color correction.
~Jess
Thanks for the tip re the 2ft 4ft mode and magenta spike, I had not realized that. I checked the ballasts when I noticed the problem and they are running in the correct mode. They seem to have stabilized somewhat in the last few days, so I probably should chalk it down to new tubes! They are running in an air conditioned studio, so temp is not an issue.
Thanks
Chris
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I'm always finding variations in HMIs and NEVER get absolutely pure color out of kinos.
I am doing a television shoot for ESPN at the moment. All the Kinos that I am using are new, the tubes are all ostensibly from the same batch, also new. They difference in the magenta output to the naked eye is amazing!
some of them look fantasic, but the rest are just so different! I am finding a huge magenta spike with some of the tubes.
I have a very good ccu department that I am working with and so far they have been able to correct it without me using plus green, but I was very surprised!
cheers
Chris
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It sounds like spacelights, in the studio, are the answer to an awful lot of problems.
they are.... but they can create a headache when you have to rig 46 of the 6K variety in one set and all suspended from 45 ft!
Seriouly, they are very managable fixture if you take the time to set them up right, i.e with silks/blacks, tartgets in the base, or raw even for an industrial look cocoon in half blue or similar.
They do get kinda power hungry though..........
Cheers
Chris
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Power gems seems to have the best ballasts I have seen.
Hi Robert, just on the powergems issue, I have found them to be excellent with their aftersales service. No matter what time of the day or night I have been able to get answers and even schematics for their gear and various pigtails at the drop of a hat.
The only problem that I have encountered with powergems ballasts was when I was running them in a 47 degree celsius environment, they were unable to cool themselves and started shutting down on thermal protect mode. Can't exactly blame them for that!
cheers
Chris
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Unfortunately i dont have any pictures, but i recently worked a week of dailies on an american wartime series over here in OZ. The scenes that we were shooting did this exact effect. The rig is probably a severly out of your budget range, but i thought it would be interesting anyway. Rigged either side of the set there was a couple scaff towers one about 120ft scaff tower with two high tension cables running about 300ft to the other, a 10ft scaff tower. On the cables ran a sled that had a lamp underslung. The lamp was custom made lamp and consisted of 16 blondie lamp holders loaded with 2k lamps. Basically tensions was released to the sled and it powered down the cable, a dimmer operator controlled the intensity of the light to simulate the flying flare.
I can imagine you could get a grip to build something like this on a much smaller managable and cheaper scale. The man hours that went into building this particular flare rig were incredible.
Hi Matthew, sounds like a massive rigging job for that effect! Is that the production in FNQ that moves down south at the end of November? If so then I am working on the same thing. The studio and location setup down here is Massive!
Cheers
Chris
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yeah, tough spun in my opinion is best suited for ENG run and gun since it stands up to months of abuse before showing wear. If your looking very diffused soft light and your on a more production basis then 216 or 250 is your best bet.
I agree, I use spun quite a bit on outdoor stuff for the reasons that you have mentioned, but also because of the noise factor in diffusion. Sometimes in a windy environment you can get that horrible flapping sound out of diffusion, and when you are time critical it is often easier to use spun.
Saying that, I love the look of 216 and 250, its much less harsh.
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First these are NOT HMI these are HID. They have a average color temp of 5200 k. They are workable but the ballast is delicate. I bought one to try it out and see. It is very sensitive to power range. I had a very hard time with getting the light to strike on certain power circuits. I them had a ballast fry. Since these are just HID lamps and ballasts, I have been looking for a comparable ballast via electric supply houses. I wouldn't recommend them. reliablity is just not worth the $.
I agree Robert, but its not just the reliability, its also the color spectrum produce by the various types of commercial HID lamps. Some of them have a huge green spike whilst others end up quite magenta.
I was lighting for a TV show covering an international rugby test, and even the lamps lighting the field had huge green spectrums. My only way out of it was to use 1/4 green on my lamps to correct the talent in the shot to closer to the background color, then CCU had some chance of getting a balanced image.
Sometimes the cheaper lamp types can end up causing you more headaches than if you just used to proper source in the first place.
Chris
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I've never used one myself, but I hope to sometime soon. Just the stats on the smoke's hangtime makes me wanna give it a shot. With the store bought heated glycol foggers, the smoke dissipates rather quickly. It does its job on a limited budget though.
Oil Based hazers such as the DF-50 will always provide a longer hang time than smokers, but be warned, in very large extended doses you can end up with residue on equipment, not very cool for lenses. I have seen equipment come in from niteclubs and the like where some internals were caked withoily residue. Once again that is in a large volume of constant exposure.
Chris
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Would dust work? Like using chalk dust or something?
Possibly, but its a bit hard to control, and your sound recordist is going to be quite annoyed at everyone sneezing and coughing....
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Hello,
Has anyone ever used incense smoke to create atmosphere in a scene through which shafts of light can be seen? I know that most people use a fog machine, but I have been recently advised to try out incense..has anyone tried this principle before?
Never heard of anyone trying the incense thing, so I cant say. I have always used oil based hazers.
Perhaps try renting a Hazer for a day and try that. Something like a DF-50 or a Swefog. They are an oil cracker and give you more of an atmospheric look than a smoke machine.
Cheers
Chris
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Some Rental in Poland doesnt want to give me a 4 k arrisun if I wanne run it with a 5.5kw honda generator, because they think the lamp could break down.
So because I didn't believe that, I spoke to ARRi Rental in Berlin an they said, that nothing could happen exept that the power supply unit could shut down the lamp because the voltage is going to much down. But that could cause nothing worse than that we have to reshoot the scene!
Does someone know anything contrary!?
Thanx for the help
Hi Max.
I presume the voltage over in your part of the world is 240v 50Hz.
That being true, you might JUST get away with using the 4K on a gennie that small, but I would only think so if you are using an electronic ballast.
We had some Filmgear heads and powergems ballasts that I ran a test with. Using a tong meter I measured the current draw on strike to be around 4 amps, ramping up to about 16-17 amps at full running temp.
If you are using magnetic ballasts (if I remember correctly), the reverse is true. You will see a Current spike on lamp strike. Depending on things like the age of the lamp, and the condition of the capacitors in the ballast, this could be anything from 20A to 40A! The spike then will ramp down and settle at probably close to 20A.
As someone else has mentioned, 5.5kW is the maximum that the gennie will deliver, which is around 23A.
if you exceed the rated ampacity of the breaker on the Gennie, it should just pop, but you should leave a little bit of time for it to cool down, as they trip easier once they are hot! ( At least that is what I have found sometimes).
As far as the honda goes, I think it is one of the best small gennies around, quiet and reliable, I doubt that you will damage the lamp by driving the gennie hard. With the later model electronic ballasts, they will usually shut down before they are affacted by under or overvoltage.
Personally I would try to find a bigger gennie. To me you really don't have much headroom left to play with.
I hope this has helped you somewhat.
Please chime in anyone if my maths is somewhat screwed up.....
Cheers
Chris
Australia
Powergems ballast hum
in Lighting for Film & Video
Posted · Edited by Chris Schlaghecke
You beat me to it Tim, I would seriously look at the fans in the ballast, that is probably one of the only areas in the powergem ballasts that can make the kind of noise that Michael is describing.
Check to see that it hasn't been dropped at some stage and that the fan is not hitting the casing. Alternately it could be the bearings, which is not so easy to fix, but if all else fails try some lubricant spray on them, preferably after removing the fan from the ballast!
Michael, if you still need help PM me and I can shoot you the email address of one their UK service techs. The powergem guys are dynamite about their aftersales support. I have been in a couple of tight spots and they have been most forthcoming in their help. At ALL hours of the day!
Make sure you let your rental shop know about it so that they can A: fix it. and B: perhaps do something about your rental bill......
Off topic a little......I have noticed lately that I get a large amount of ballast squeal from powergems if I am using a double ended lamp, especially in a strand 2.5K Hmi softlight. Anyone else noticed this?
edit: fixed typos