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What Source Four To Use?

Discussion in 'Lighting and Electrics' started by lighttechie5948, May 12, 2008.

  1. lighttechie5948

    lighttechie5948 Active Member

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    Whats the formula to figure out which source four to use.

    I have to project Gobos onto the Cyc for a top notch dance production.

    The Information I have is the length of the stage, the width from 1E to Cyc, and the height from the stage to 1E.

    I want some of the gobos to fill 1/3 of the cyc (small stuff like staircase gobos and center gobos). And some of them to fill the entire cyc (like forest gobos)

    Any help is appreciated.

    ~Joe
    Production Manager/Lighting Design
    Dance Connection
     
    Last edited by a moderator: May 15, 2008
  2. len

    len Well-Known Member

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  3. zac850

    zac850 Well-Known Member

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  4. Charc

    Charc Well-Known Member

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    Sir, I take offense.
     
  5. Grog12

    Grog12 CBMod CB Mods Premium Member

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    Follow the link provided. Draw yourself a quick little section in scale with the cyc in place and the first electric in place. Measure the distance from 18" below the first electric (where the instrument would be hanging) to where you want it projecting on the cyc (up and down) Multiply that by the field angles provided in the above links to figure out the diameter of the light.

    This is the quick down and dirty way. By no means will it be 100% accurate but it'll be close enough.
     
  6. Sean

    Sean Active Member

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    why?

    --Sean
     
  7. Charc

    Charc Well-Known Member

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    I guess it doesn't matter, and leko does roll off the tongue better than some of the alternatives... However, just as I don't think a tissue should be referred to as a Kleenex, I don't necessarily believe a S4 should be referred to as a leko. In my mind, "S4" is sufficient. If it is a S4 PAR, then it should be referred to as a S4 PAR, but a S4 ERS should need no modifier.
     
  8. len

    len Well-Known Member

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    Yes, I know the ETC fixture is not the first leko, but it's easier to type than ellipsoidal.
     
  9. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

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    You my friend need to learn about Photometrics. The standard answer is buy the Photometric Handbook and you will be set. However, in this modern world we have spreadsheets to cheat for us! Go to our own Dereklefew's web page and download the latest version of his photometric spreadsheet. With it you can enter the distance and it will calculate how large of an area the light will illuminate and how bright it will be. You should have an output of about 100 lumens as your goal. A little less than that is ok, but a lot less than that and your images will be very hard to see.
     
  10. Sean

    Sean Active Member

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    Just a word of advice:

    Don't get hung up on terminology. You'll just annoy the people you're working with. "Leko" has very much become a term to describe ANY ellipsoidal fixture. You'll find designers that still notate their plots with 6x9 when referring to a 36° (and rental shops do sometimes as well).

    Just my $.02

    --Sean
     
  11. Charc

    Charc Well-Known Member

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    Yea Sean, I realized this point as I was typing my last post, but did not feel like conceding defeat at the time.

    The 6x9 / 36º is interesting though, hadn't heard that before. I take it that wouldn't happen in a plot wit S4s and 360Qs though?
     
  12. tgates

    tgates Member

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  13. Dustincoc

    Dustincoc Active Member

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    Hope they don't send me 36° when I want a 6x9.
     
  14. TimMiller

    TimMiller Well-Known Member

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    search around for LD calculator lite. Its a free program and it will help you out. It also does rigging loads, lighting loads, feeder calculations, dimmer schedules along with ML schedules.
     
  15. Footer

    Footer Senior Team Senior Team Premium Member

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    Most places carry either or, or if they carry both you have to specify (odds are your budget does the specifying). Most shows that tour without a plot will default to doing their plots with 6x9's and par56/par64s. Venues that have S4's will plot what they have of the S4 stock. I have worked in several places that have their 26s, 36s, 19s, and 50s, marked at 6x12, 6x9, 6x16, and 6x4.5, just so if they plot says 6x9, the local guy will go and grab a 36 and not get confused.
     
  16. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    You might also check into this web (flash)-based visualizer program: http://design.cablepick.com/gobo
    It won't give information on projected size, but can be a handy tool to decide which gobo(s), color, and focus to use. Particularly useful if using a double rotator or stacking gobos in an ML.

    Remember that all photometric data is based on a full, open, gate [3.25" in the case of a SourceFour™ ("A" size max. image=2.95"; "B" size max. image=2.53")] so after calculating the pool size multiply the resulting diameter by (diameter of gobo image/3.25) to get the projected gobo size.

    See also this and that PDFs from ETC. Also, this interactive site from ETC.

    However, I still prefer my Photometrics Wooksheet.:) Hope this helps.
     
    Radiant likes this.

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