shutter speed rule for hand-held shots

Discussion in 'Digital Cameras' started by OlEnSh, Sep 10, 2003.

  1. OlEnSh

    OlEnSh Guest

    there's a rule of thumb in SLR photography which says that if you use a x
    mm lens, then your shutter speed should not be less than 1/x s, to avoid
    blurring due to camera shake when you don't use a tripod. e.g. if you use
    300mm, then shutter speed should be more than 1/300s.
    how can this be applied to digicams, since their lens actual focal length
    are shorter than the SLR equivalent? is the figure taken the equivalent SLR
    focal length or the digicam's focal length?
    OlEnSh, Sep 10, 2003
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  2. OlEnSh

    Graham Guest

    What is important is the angle of view of the lens and the duration of
    the exposure. The rule of thumb is based on an assumption that a
    handheld exposure involves movement of the camera at a rate which is
    independent of other factors.

    Thus, as the lens becomes longer, the angle of view becomes smaller, the
    relative effect of a given amount of movement on the image becomes
    larger, and so the duration of the movement needs to be reduced by using
    a faster exposure.

    Or more simply, double the lens length, halve the field of view, double
    the effect of movement, so halve the duration of exposure.

    It's just serendipity that for a 35mm camera the acceptable exposure is
    about 1/f.l. (f.l. = focal length) and not 7/f.l. or 0.15/f.l.

    For a camera with a different sensor system and hence different lens
    lengths for the same image proportions, what matters is the field of
    view. So if the total movement at 1/250sec is acceptable for a 250mm
    lens on a 35 mm camera, it should also be acceptable for a 25mm lens on
    a digital camera if the field of view is the same.


    Others may agree with me or they may tell me I'm dreaming, but I am
    finding that I can go somewhat slower than this rule of thumb suggests
    with my non-slr digital camera.

    Presumably this is because there are no significant moving parts to
    shake the camera. The shutter/aperture mechanism is rotationally
    symmetrical, with no net "shake" of the camera, so the camera is far
    smoother than a 35mm film camera with a mirror and two shutter blinds
    hurtling about inside it.
    Graham, Sep 10, 2003
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  3. OlEnSh

    Todd Walker Guest

    You must use the equivalent 35mm focal length to figure the minimum
    shutter speed.

    Todd Walker
    Canon 10D:
    My Digital Photography Weblog:
    Todd Walker, Sep 10, 2003
  4. If your camera has or *can* have a fairly conventional neck strap,
    then push the camera *away* from you until the neckstrap is tight, and
    pull your elbows in to your stomach. You've now got the camera held
    in a *very* stable position (I find I can shoot this way at much
    slower shutter speeds than I can pulling the camera up to my face) and
    you can still see the LCD. One of the best things about consumer
    digital cameras.
    David Dyer-Bennet, Sep 10, 2003
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