Kodak DX-4530 and 'exposure' time.

Discussion in 'Kodak' started by Evan Platt, Nov 3, 2004.

  1. Evan Platt

    Evan Platt Guest

    I have a DX4530, and like to take pictures of airplanes and
    helicopters. I'm encountering rotor freeze effect - like this shot,
    http://home.espphotography.com/rotorfreeze.jpg . I set the exposure
    time to +1.5, but this didn't seem to have any effect (as a matter of
    fact, this was at 1.5. Did I need to set it higher? Or do I need to do
    something else?

    FYI, I'd like a more 'moving effect' of the rotors, like
    http://www.fach-extraoficial.com/fotos/noticias/rapaz_1.jpg .(not my
    photo).

    Thanks. :)

    Evan
     
    Evan Platt, Nov 3, 2004
    #1
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  2. Evan Platt

    Owamanga Guest

    What the hell is exposure 'time'?

    You need to have control of the shutter speed, make it slower. I guess
    around 1/60th - 1/30th sec.

    Each helicopter is different, but a small one has a rotor RPM of about
    400, which is 6.5 revs per second or 0.15secs per rev. Your heli had
    4 blades which means for a completely smooth image you would need to
    slow the shutter to 0.0385 seconds - about 1/25sec, which allows for
    the set of 4 blades to do a one-quarter revolution.

    Your sample 'good' picture didn't wait that long (each blade is still
    distinguishable) so I'd guess the shutter speed was about half that at
    1/50sec. Closest you can probably set on the camera would be 1/60th.

    Go too slow and you'll have problems with the helicopter movement, too
    fast and you'll get your 'rotor freeze' effect.
     
    Owamanga, Nov 3, 2004
    #2
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  3. Evan Platt

    Evan Platt Guest

    Sorry my bad - it's 'exposure compensation' on the 4530.
    Actually I found it. My goof of calling it exposure time - it's called
    "Long time exposure". My choices are .7" or 1.0 (well, and others). So
    I guess I'll experiment with that.

    Thanks. :)

    Evan
     
    Evan Platt, Nov 3, 2004
    #3
  4. Evan Platt

    Owamanga Guest

    Unfortunately, I think 0.7sec is going to be way too long, if your
    camera won't let you control shutter speeds below that, you might need
    to look at getting a different camera.

    At 0.7sec, the helicopter itself will probably blur because of it's
    own movement. (Unless it's still on the ground and you are using a
    tripod)
     
    Owamanga, Nov 3, 2004
    #4
  5. Evan Platt

    Big Bill Guest

    If this is your camera:
    http://www.kodak.com/eknec/PageQuerier.jhtml?pq-path=1156&pq-locale=en_US
    you have very little control over the way the camera takes photos. The
    only exposure control is program mode, meaning the camera does it all
    for you, except that "Long time exposure" mode, which probably won't
    work for what you want, because the chopper will move in that .7
    second.
    You do have, though, the option of using a neutral density filter;
    this will reduce the amount of light entering the lens, and will very
    probably slow the exposure down in program mode.
    Good luck.
    Bill Funk
    Change "g" to "a"
     
    Big Bill, Nov 4, 2004
    #5
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