Removing diffusor from an LED light bulb

Discussion in 'General Electronics Chat' started by HenryTj, May 18, 2016.

  1. HenryTj

    Thread Starter New Member

    May 18, 2016
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    I'm reposting this because somehow the post title got wiped out.

    Repost

    I do photography and no-budget short film making. I'm always looking for the cheapest lights I can find. I bought a package of GE Bright Stik to try out. I'm looking for lights that take up the least volume of space. The thin cylinders of the Bright Stik are a good candidate. In general photography I know that diffusing a light often cuts the light that reaches the subject by about half. So I carefully cut off the diffusor cap (if that's the right term) off one of the Bright Stik bulbs. Using my light meter I was surprised that the light reaching the subject was nearly 4x as bright. Given that without the diffusor cap the pattern is 180-degree spread. So putting the bulb in a reflector boosted the the light to the subject by about another 30%. Wow. So from a 60w equivalent bulb I got about 300w worth of light.

    However, is this a bad thing to do? I can imagine that the diffusor cap maybe protects the LEDs from the air. Maybe the inside of the cap was filled with nitrogen or something to keep oxygen away from the LED or at least dust. So might doing this cause the LEDs to burn out. Does anyone know?

    Also might the diffusor cap do more than just diffuse the light? Might it have a "phosphor" chemical that adjusts the spectrum?

    I thought I should ask before buying and modifying an 8-pack or suggesting this to other filmmakers. I see that there are 100w equivalent Bright Stiks. If the same works for those as it did for the 60w, it would result in a 500w equivalent light source for just under 20w of power consumed. I could get 2kw of relatively cool lighting (often needed in film) for just 100w of power. That's a important consideration when trying to light a horror movie scene in an old house with questionable wiring.

    Thanks.
     
  2. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    People have been using LEDs out in the open air since they were first created. They will be fine. In fact, by exposing the elements to the air they will probably run cooler and longer that a still intact unit.
     
  3. HenryTj

    Thread Starter New Member

    May 18, 2016
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    Thanks. That is what I was hoping to hear.
     
  4. HenryTj

    Thread Starter New Member

    May 18, 2016
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    Just LEDs are often encapsulated in epoxy or some similar material. I was sure if a bare LED would have problems.

    Thanks
     
  5. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Some bare white LEDs have significant UV emissions so the white diffusor plays a role in absorbing the residual UV. If your actors get a noticeable tan after a scene, you may want to replace the diffusor.

    Also, bare LEDs are a point-source of light. Your actors may complain that they are blinded for seconds to hours from looking directly at the light - even long-lasting streaks across their field of vision from accidently scanning a room and looking at the light source. If they look long enough, damage to sight has occurred. See safety warnings on some of the LED suppliers websites - Cree, Phillips LumiLED, Osram-sylvania, ...
     
    jsallas likes this.
  6. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    Don't you find that "cheap" solutions are inferior at color rendition?
    Maybe you don't care...
    Most "photography" lights like that are all using high 90+ CRI LEDs ($$)... Cheap bulbs won't produce colors correctly..

    Of course I'm sure color rendition is the least of your problems with low/no budget films...


    as to the diffuser.. Its fine to remove it..
    The intention of that light is to provide nice "diffused" light.. Your needs are different.. Go for it..
     
  7. GopherT

    AAC Fanatic!

    Nov 23, 2012
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    Some digital cameras (even cell phones) do an incredible job of color correcting on the fly. It may not be the "Correct" correction but the feature is there.
     
  8. HenryTj

    Thread Starter New Member

    May 18, 2016
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    That is possibly the case and I do care. But as you saw, my budget is limited. I'm on below poverty line disability once a month income. Without cast and crew volunteering I can't do anything. I'm shooting on an older Canon 60D I got as a factory refurbished clearance discount after the 70D came out two years ago. So I'm at that level where anything is better than nothing.

    I've seen samples of what good movie colorists can do and it's quite amazing. IF they can take bluish outdoor footage and make it look lush and warm, then I'm sure they can improve on my lighting. At worse I can make the footage b&w. And when it comes to shooting horror, I don't think horror fans are picky about the color as long as there is fun horrific action. Once I've put together a "body of work" I might be able to secure funding and then can improve the equipment including the lighting.
     
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