why aren't built-in flash place farther away from the lens?

Discussion in 'Digital Cameras' started by peter, May 26, 2004.

  1. peter

    peter Guest

    Small cameras tend to produce red-eyes. Tha's why many Kodak and Sony
    cameras distance the flashes from the lenses. But many camera makers seem to
    like to put the flash near the lense (e.g. canon elph series, the flash
    could be placed on the other corner). Why?

    Take the HP photosmart R707. It has a feature to digitally remove red-eye
    after the shot is taken. Yet the flash is placed very close to the lense, as
    if red-eye is not a concern.
     
    peter, May 26, 2004
    #1
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  2. peter

    Lionel Guest

    Because people like small cameras. If the camera is tiny, how can the
    flash *not* be close to the lens? An inch or two isn't going to make
    much difference.
     
    Lionel, May 26, 2004
    #2
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  3. peter

    Ian Stirling Guest

    If you can focus on something closer to you than the camera, so that
    the lens and the flash blur into one, then the red-eye gets MUCH
    brighter.
     
    Ian Stirling, May 26, 2004
    #3
  4. Moreover - a small flash that far away from the lens will
    cast horrible shadows. Red eyes you can remove, shadows
    you can't.


    /Roland
     
    Roland Karlsson, May 26, 2004
    #4
  5. peter

    Ron Andrews Guest

    3 to 4 inches between the lens axis and the flash is good enough to
    prevent red-eye in most cases. A telephoto shot requires more, but how often
    do you have someone looking straight at the camera in a telephoto shot?
     
    Ron Andrews, May 26, 2004
    #5
  6. peter

    Ron Andrews Guest

    Cameras designed for the Asian market are less likely to have good
    red-eye reduction. (I agree with Peter that "good" red-eye reduction as
    adequate distance between the lens and flash.) Asians have different
    coloring in their retinas that make red-eye less objectionable. Kodak got
    burned in 1972 with the Pocket Instamatic camera that had terrible red-eye.
    Since then, many (but not all) of their cameras have had decent lens-flash
    separation. Sony has been a little more attentive to non-Asian markets.
     
    Ron Andrews, May 26, 2004
    #6
  7. peter

    Ron Baird Guest

    Hi Peter,

    The "red-eye" phenomenon has been familiar to photographers since the
    introduction of synchronized flash picture taking. It is caused by the
    reflection of light off the blood vessels of the retina of the subject's
    eyes. It occurs most often when the flash is located close to the
    picture-taking lens of the camera. It was not as well known until smaller
    cameras were introduced in the early 70's however, and some fixes were tried
    to overcome the issue, i.e. Flashcube extenders for pocket cameras. Also,
    red-eye wasn't so common with older, bulkier cameras that had separate flash
    units. These units were attached to a handle or flash bracket several
    inches away from the lens, or the Flash could be detached and held away from
    the camera. With today's smaller cameras with built-in flash, the flash is
    closer to the lens.

    The red-eye effect tends to be more evident when the subject is young and
    has blue or gray eyes, which reflect more light than darker eyes. Children
    have larger pupils and less pigmentation than adults and they transmit more
    light back to the camera lens. In fact, however, it is the reflection of
    the blood rich pupil that is reflected back due to the close angle of the
    light source to the lens.

    The following techniques can help reduce red-eye:

    * If the camera has the red-eye feature, set the Flash Mode to red-eye.
    * Increase the level of light in the room by turning on all the room
    lights. The added light will cause the subject's pupils to contract,
    reducing the reflective surface that causes red reflections.
    * Have the subject look at a bright light (for example, a room lamp or a
    ceiling light) just before you take the flash picture. The bright light will
    reduce the size of the subject's pupils
    * Red-eye is the worst when the subject's eyes are off-center in the
    picture so if possible, center your subject and have them look directly at
    the camera.
    * If your camera has detachable flash capabilities, move the flash away
    from the camera lens. If the camera has these capabilities, you can also
    attach the flash to the camera with a flash cord and handhold it or clamp it
    to a nearby object.

    Note: The following techniques may not eliminate red-eye completely. If
    you have a digital camera, you can easily remove red eye by use of software
    to remove the red-eye that may be present.

    Talk to you soon,

    Ron Baird
    Eastman Kodak Company
     
    Ron Baird, May 26, 2004
    #7
  8. Nope - you will still get red eyes.

    Sometimes I think it is even worse when someone looks "away".


    /Roland
     
    Roland Karlsson, May 26, 2004
    #8
  9. Take a closer look at the Elph series. The right-hand end of the camera
    is pretty much completely filled by the battery and the CF card lying
    side by side. There isn't much room for anything else on that end of
    the camera except some controls on the top and rear of the case -
    certainly not enough room for either electronic flash circuitry
    (reflector and capacitor are the large bits) or for the zoom lens plus
    CCD. So those get placed over towards the left side.

    In addition, you have to hold the camera somewhere, and both flash and
    lens have to be placed where your hand won't cover them. There just
    isn't much choice of locations that satisfy all these constraints on a
    small camera.

    Most tiny cameras from all manufacturers have this problem, except the
    ones with no flash at all.

    Dave
     
    Dave Martindale, May 27, 2004
    #9
  10. peter

    Ron Andrews Guest

    I agree the lens focal length is not the determining factor, but it is
    often related to red eye. The primary factor is the minimum angular
    separation between the lens and the flash. In telephoto shots, the subject
    is often farther from the camera. This reduces the angular separation. The
    aperture of the eye and the aperture of the camera lens are also important.
     
    Ron Andrews, May 28, 2004
    #10
  11. peter

    Lionel Guest

    Kibo informs me that (Georgette Preddy)
    stated that:
    There's some truth to that, but it's not the whole story. Direct flash
    is fine when stopped down, or diffused (eg; with a Lumiquest or
    similar).
    Well, you won't get any argument from me on that point. ;)
     
    Lionel, May 31, 2004
    #11
  12. Oh yes they do. They work fine for "fill flash".
    They also work well for press and sports where you have no option for
    setting up studio lighting.

    Of course, you can go to a real powerhouse like the old Vivitar 285
    and get the proper exposure across a basketball court. (blinding the
    players as well) <:))

    Roger Halstead (K8RI & ARRL life member)
    (N833R, S# CD-2 Worlds oldest Debonair)
    www.rogerhalstead.com
     
    Roger Halstead, Jun 1, 2004
    #12
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