Page 3 of 3 FirstFirst 123
Results 21 to 26 of 26

Thread: Help my friends from going blind

  1. #21
    Join Date
    Aug 2008
    Location
    UK
    Posts
    5,704

    Default

    Quote Originally Posted by PUFF1N View Post
    Thanks so much guys. I will be learning a lot more around mpe and the simple breakdown here is invaluable. Were on tonight and I've managed to help the DJ understand the dangers. I'm going to project the animations up on the celing. Looks good and no direct exposure. Nill reangle for some beam shows later using green only and moving quick. No single beam at all, plus I will remind everyone not to look at it. Thanks again. I'll be around more often as I've well and truly caught the laser bug.
    It doesn't take a single beam to burn your eyes. A fence or fan is still the same, its a single beam moving so fast from left to right that your eyes see a solid shape due to persistence. Granted a static pencil beam is far more dangerous but don't believe that because a projection is a fan etc there's no danger. The danger in a static pencil beam comes from the fact that its not moving so dwelling on the eyes permanently, that's all. With a fan you have the same situation but this time the dwell time is decreased slightly by a series of repeats so there are short millisecond breaks between repeat exposure as the beam scans from left to right then repeats. If over MPE, the static beam burns quicker but the repeated beam still burns.

    The only safe way to do beams without calculations etc is to project them overhead. No need to tell your audience not to look at them, provided you keep them overhead and directly out of their eyes.

    What you want to avoid at all costs is projecting beams down into your audience's eyes. So position the projector so the lowest scan angle it can achieve is still above the audience.

  2. #22
    Join Date
    Aug 2008
    Location
    UK
    Posts
    5,704

    Default

    Here's a fanned effect burning a camera sensor:


  3. #23
    Join Date
    Aug 2008
    Location
    UK
    Posts
    5,704

    Default

    and beam strikes on this one:

    (At the end the sensor is shown recording a sheet of white paper where the hits can really be seen)


  4. #24
    Join Date
    Apr 2006
    Location
    Miami, FL
    Posts
    3,590

    Default

    Quote Originally Posted by White-Light View Post
    Here's a fanned effect burning a camera sensor:

    yes thats a great video.. I wonder what it is about the 5D II that makes it die when it gets a laser impact...

    my 1D and 1D II have both had hundreds of laser impacts at various LEM's and have never had an issue at all

  5. #25
    mixedgas's Avatar
    mixedgas is offline Creaky Old Award Winning Bastard Technologist
    Infinitus Excellentia Ion Laser Dominatus
    Join Date
    May 2007
    Location
    A lab with some dripping water on the floor.
    Posts
    9,890

    Default

    My guess is a "HYPER-HAD" or similar type ccd with the individual micro lensing on each pixel.

    Steve

  6. #26
    Join Date
    Jan 2007
    Location
    Florida
    Posts
    4,382

    Default

    A lens on each pixel??? What's that, about 10 million lenses or so ? wtf .. :0

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •