Sony TRV-900 Problem - light then dark then light then dark . . . . HELP Please

Discussion in 'Amateur Video Production' started by kevin, Dec 27, 2006.

  1. kevin

    kevin Guest

    I love this DV Camcorder, but for certain effects, especially LED and
    other Specialty lighting effects, it is VERY inconsistent.

    Here is a short sample video to show you what is going on:

    http://www.infocellar.com/sample.wmv

    It's TERRIBLE !!! I am trying to make a demo video of the
    "Hypnocube" and as you can see it is not working out. The Hypnocibe
    is an amazing LED invention that 2 guys made in their basement (see
    www.Hypnocube.com ). I paid $380 for the device.

    As the video shows, the LED's are changing rapidly, and when a lot of
    them come ON - especially when they are all Blue - the background
    becomes very dark. It seems like the camera is compensating
    automatically for the excess light that the LEDs are outputting. I
    had the same problem when I filmed my power supply, which has Blue LED
    fans to cool it . . . the entire room showed up as very dark.

    I thought, "OK no problem, I'll just turn the White Balance and the
    exposure to "Manual mode" by sliding the slider on the front left
    down, and then adjusting the settings manually with a wheel on the
    front" BUT NOOOOOOOO - I did all that and it had no effect.

    I have tried everything to make the background appear as IT REALLY IS
    - just a constant lighting on my kitchen counter. The only thing
    changing intensity is the LEDs.

    I am beginning to think that this is simply the way this camcorder
    works - and that there is no "fix". What do you think?

    If it is just the way it works - can anyone recommend a good unit that
    will NOT do this ??? This unit is old and I would not mind buying a
    new one - but I di want to complete this video while keeping the
    background lighting constant. Thanks !!!
     
    kevin, Dec 27, 2006
    #1
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  2. Huh? Who switched on the "message recycler"?

    -m-
    --
     
    Martin Heffels, Dec 27, 2006
    #2
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  3. What are you talking about? The only thing on the front left
    of my TRV900 that could be described as a "slider" is the
    auto/manual FOCUS control. Why were you playing with that?

    Your problem is that your camera is operating in full auto-
    exposure (which would account for the light/dark problem),
    and likely auto-white-balance, also. You need to turn both
    of these OFF.
    You clearly haven't tried actually turning off the auto-exposure.
    I think you need to learn how to use your camcorder.
    You have a unit that will do the job just fine.
    Learn how to use it properly.

    I hope you aren't the same guy that came through here a year
    or two ago with exactly the same problem with his glowing-egg
    "orbs".
     
    Richard Crowley, Dec 27, 2006
    #3
  4. Do you think this is the same guy who came through here a
    year or two ago with his cycling-color magic-egg "orbs"?
    Let's hope not.
     
    Richard Crowley, Dec 27, 2006
    #4
  5. Martin Heffels, Dec 27, 2006
    #5
  6. kevin

    Luis Ortega Guest

    I have a trv900 and always shoot in manual exposure mode for unusual
    situations like you describe and the results are fine. There is no reason
    why you can't use manual exposure control to get the correct exposure. Try
    it.
     
    Luis Ortega, Jan 10, 2007
    #6
  7. "Luis Ortega" wrote ...
    Alas, he thinks that by switching the Auto-Focus switch on
    the front of the camera, he is somehow affecting the auto
    exposure and white balance.
     
    Richard Crowley, Jan 11, 2007
    #7
  8. This seems a good place to put my 2 cents into this thread.

    Many devices that have LEDs feed them pulsed electricity, that is, the
    LEDs are flashing some number of times per second, fast enough to make
    them look steady to the human eye (just like movies and TV!). You can
    often see this by waving the device rapidly in the air - the LED shows
    up as a series of dashes instead of a continuous line. Note: choose a
    small device for this experiment :)

    Now try to make a video of these, exposing at ~60 fields/30 frames per
    second. You would naturally get a strobe effect, which would show up as
    - Tada! - variations in brightness, if the LED pulse rate is not in
    exact sync with the field/frame rate.
     
    Gene E. Bloch, Jan 11, 2007
    #8
  9. "Gene E. Bloch" wrote ...
    Indeed, and many higher-end cameras have adjustments
    for shutter speed, etc. to accomodate this kind of thing.
     
    Richard Crowley, Jan 11, 2007
    #9
  10. Shutter speeed isn't the problem, frame rate is.
     
    Gene E. Bloch, Jan 12, 2007
    #10
  11. I think it's more to what Richard is referring to. "Clear scan", and this
    is varying the shutter-speed to reduce flicker (like on television and
    computer-monitors in frame).

    cheers

    -martin-
    --
     
    Martin Heffels, Jan 13, 2007
    #11
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