Blinking eyes? Who passed wind?

Discussion in '35mm Cameras' started by Bot-tastic, Jul 28, 2003.

  1. Bot-tastic

    Bot-tastic Guest

    At what speed to eyelids blink. If I do a long shutter speed and the person
    blinks with the shutter open and has the eyes open when the shutter closes
    will that make the eyes unclear?
     
    Bot-tastic, Jul 28, 2003
    #1
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  2. Bot-tastic

    stan Guest

    I have never heard that question asked in all my 50 years!! LOL!!! I can't time
    mine, but I bet some one has timed them. My guess is that if the shutter is
    slow enough to capture a blink it would show as a blur, but the eye itself
    would be sharp. Like shooting a flag in front of a building.
    Stan
    Visual Arts Photography
     
    stan, Jul 29, 2003
    #2
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  3. Bot-tastic

    Alan Browne Guest

    I shot a roll of a fellow a few weeks ago and he managed to blink on a
    couple of them. The flash duration is on the order of 2 ms (1/500) and
    the eyelids look unblurred in half travel. So it isn't as quick as we think.

    literature says: ". It was found that the EMG pattern consisted of a
    single pulse envelope for each of the orbicularis oculi and levator
    palpbrae superioris, which lasted for an average of 129 and 195 ms
    respectively."
    http://brl.ee.washington.edu/reports/papers/Rep016.html

    So let's say your exposure is 1/15 (66ms), and the fellow blinks, then
    the event will mask his eyes for about twice-thrice the time. You would
    have closed eyes on your film unless the blink starts quite late.

    To have the eyes "burn through" the closed eyelids (which are darker),
    let's assume a 2.5:1 time ratio of the worst case (195ms or let's say
    200ms) X 2.5 = 0.5 seconds. If your exposure is 1/2 sec or longer,
    then a natural eyeblink should not show.

    Any slower than than that and I doubt it would be very noticeable.

    Anyway that is my guess!

    Cheers,
    Alan.
     
    Alan Browne, Jul 29, 2003
    #3
  4. Bot-tastic

    NickC Guest

    I can't validate this but at one time I think I read where the eye
    blinks at 1/60th of a second.

    Nick
     
    NickC, Jul 29, 2003
    #4
  5. Bot-tastic

    David Guest

    I found this thru Google:

    Date: Thu Nov 19 19:29:11 1998
    Posted By: McWilliams, Grad student, Optometry, University of Missouri- St.
    Louis
    Area of science: Medicine
    ID: 911393437.Me
    ----------------------------------------------------------------------------
    ----
    Message:


    Brent:

    The average time it takes for a complete human blink is about 300 to
    400 milliseconds or 3/10ths to 4/10ths of a second. Of course this is an
    average only and can differ from person to person. Also, there are other
    factors that can affect blink speed, like fatigue, medications,
    diseases, and injury to the eye area. Most factors decrease or slow the
    blink rate.
    Good luck!

    Now, can any math whiz come up with how this translates into the
    photographic/shutter speed standard of 1/x sec?

    Dave
     
    David, Jul 29, 2003
    #5
  6. 1/50th sec.
     
    Michael Scarpitti, Jul 29, 2003
    #6
  7. http://plaza.ufl.edu/stiney/eyeblink.jpg

    1/8.4 second according to EXIF.
     
    Phil, Squid-in-Training, Jul 29, 2003
    #7
  8. Bot-tastic

    Bot-tastic Guest

    Bot-tastic, Aug 6, 2003
    #8
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