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Brian Doran

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  • Occupation
    Industry Rep
  • Location
    New York
  • Specialties
    ARRI Lighting Product Specialist

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  1. Is there any chance it was the Licht- Technik Bag-O-Light? https://www.licht-technik.com/en/produkte/bag-o-light/
  2. Just chiming in to say that the ballast in the photo is from 1995, about 26 years old. The last two digits on ARRI ballasts represent the year of manufacturing.
  3. The lack of dimming is the only limitation to consider when using the S360s in high-speed mode. If you don't need the full beam spread, it might also be a good opportunity to use an intensifier on that head, I'm surprised they're not used more.
  4. Sure thing, I'll send you an email tomorrow morning.
  5. I seems like the only online traces of Shock Stop are on your blog, Guy. Do you know who might carry them for sale or rental?
  6. I'm not sure if this is what you're asking, but the list of gels programmed into the Skypanel, and methods for achieving them with XY, HSI, and RGBW, are available on ARRI's website. https://www.arri.com/resource/blob/65960/7ad47c8a0279cd8084ee697b067f408e/arri-skypanel-gel-conversion-charts-data.zip The .zip file contains conversion charts for 3200K and 5600K, 8 and 16 bit.
  7. Here's a simple inverse square calculator that I found. That should take care of the illuminance part of the equation. The other area of interest might be the illumination area based on distance and beam angle. Here's a beam angle calculator I found. Maybe there's an app that combines these two, not sure.
  8. I'm a big proponent of comparing fixtures based on illuminance values such as foot-candles and lux, rather than luminance values given in lumens. Lumens represent the total amount of light produced by the source, be it the tungsten bulb, the HMI lamp, or the LED engine. The problem with this is that it does not account for the beam angle, so it does not speak to how wide a source is. It is also my understanding that the lumen measurements are often made independent of the fixture that the light source is installed in. As Phil mentioned, light loss in optical elements is an important factor, and this might not be represented in the lumen measurement. Let's say that five different fixtures are using the same LED engine made by Osram, well all five might list the same lumen value suppled by Osram, but this does not factor in the fixtures optical loss, reflector efficiency, etc. So, I like foot-candles and lux. These units measure the number of lumens falling over a 1 square foot or 1 square meter area. Instead of measuring just the light source in an integrating sphere like in this photo, foot-candles and lux are measured as the light falls upon a surface at various distances from the fixture. Because of this, we are able to factor in optical efficiencies that might separate two fixtures with the same OEM light engine. Most foot-candle/lux charts will also show the beam angle, illuminance, beam diameter, distance relationship. This has the benefit of telling you how large of a space the fixture can illuminate to X level at Y distance when at whatever variable focal length, if applicable. Here is an example of an illuminance photometric chart. Comparing lumens reminds me a bit of comparing the expected lifetime of LED engines. There are only a handful of LED manufacturers in the world, and our tiny little industry mostly buys from that same handful. It's the LED OEM that calculates the commonly referenced LED lifetime "L70" metric, which measures how many hours an LED engine can run before efficiency drops to 70%. That's all good and well, and it speaks to the quality of LEDs that the lighting fixture uses, but it is not analogous to the fixture's expected lifetime. When you see a streetlight flickering, it's because of an issue with the LED driver or power supply, not the LEDs themselves. The same is true in our industry, the electronics will likely fail before the L70 time is reached. This is long winded. Like Phil said, you'll probably just get used to thinking of LED, tungsten, and HMI as three different beasts and have a general sense of the different degrees of lumen-to-watt efficiency between them. Just make to sure to double-check the photometric sheets when marketing material claims that X LED fixture is as bright as Y HMI fixture. HMI is still the brightest-per-watt, and I just don't know where some of these marketing comparisons come from...
  9. Is the buzzing constant, or does the head buzz briefly and then go quiet, failing to strike the lamp?
  10. Yeah, it looks like they specify two 14.4v V-mount batteries.
  11. Absolutely agree in regards to testing and being aware of line-loss for tungsten loads. I just want to add that although electronic ballasts can regulate the mains voltage and their output voltage, you can still incur line-loss across your run of header cable. Trying to use a single 100' run instead of two 50's, metering out your header to find any high resistance wires, and keeping clean contacts can all help keep resistance and thus line-loss down. The newer ARRI ballasts now use CCL (compensation for cable loss) circuitry, wherein a feedback circuit in the head is telling the ballast how much extra voltage is needed to overcome the line-loss. helps keep things predictable.
  12. Why not just use the TM30-18 Rf scores? With 100 color samples and a very intuitive graphic showing color gamut as well as shift, I think it's pretty hard to beat. It is based on the standard human observer, much like CRI, which can be an issue, but it certainly gives us more information with more data points and is thus harder to cheat. As far as I know, TLCI is based on CCD sensors, so it might not be an accurate predictor of CMOS sensor characteristics. SSI is the only one of the three with a real advantage, being that one can easily change the reference source if they want to match non-Planckian sources like gelled lights or fluorescents.
  13. If it's anything like the old ARRISUN 12, then you cannot use the modern G38 single-ended HMI lamps, no. The sealed-PAR lamp had its own reflector, so our old ARRISUN did not have or need one. Running a lamp without this built-in reflector would likely cause overheating and damage to the fixture, as much more heat would be absorbed by the inner baffle than was planned in the design. More troubling, is the lack of UV filtering glass on the fixture, again due to the sealed-PAR's inclusion of UV filtering. This is all based on my experience with the old ARRI heads, if the Desisti heads were different, please don't hesitate to correct me. As for sourcing lamps, I find them to be rare enough that lamp failure is often reason to scrap the entire fixture. If anyone has a source, please let me know!
  14. This is just my gut feeling, but wouldn't having a focusing lens on each LED cause multiple shadow issues? A diffusion plane is really helpful for homogenizing the multiple light sources into "one" source.
  15. That is a magnetic ballast. Like Phil said, you will have to be sure to synchronize with your camera to avoid flickering, and will not be able to dim the fixture, etc.
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