Look at this guy's shot with older Olympus

Discussion in 'Olympus' started by RichA, May 5, 2005.

  1. RichA

    RichA Guest

    RichA, May 5, 2005
    #1
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  2. Randy W. Sims, May 5, 2005
    #2
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  3. RichA

    Alan Browne Guest

    IAC, the flash made the exposure not the shutter speed. Hard to say how
    fast/slow the flash cycle is on that camera however. On the order of
    1/1000 to 1/5000 most likely.

    I wish the phot were available in a larger size.

    Cheers,
    Alan.
     
    Alan Browne, May 5, 2005
    #3
  4. RichA

    Alan Browne Guest

    The EXIF claims : 1/18,000 as shutter speed. Strange. The E-20 does
    1/640 max. Maybe the camera can determine the flash duration from the
    amount of power used and calculate the duration of the flash?
    (non-linear and then some).

    Cheers,
    Alan
     
    Alan Browne, May 5, 2005
    #4
  5. RichA

    Alan Browne Guest

    Yep ... the E-20N version can go to 1/18,000 shutter speed (electronic
    shutter). So just have to fire the flash before the "shutter" pass and
    wait for the flash to reach peak discharge (about 100 microsecs) and
    then run the shutter pass.
     
    Alan Browne, May 5, 2005
    #5
  6. Hmm, that's interesting. I don't remember reading anything on electronic
    shutters. I've read a good deal about the various types of mechanical
    shutters. What is an electronic shutter? Electronically turning the
    sensor "on"/"off"? or turning the feed from the sensor to the CPU on/off?

    That still seems incredibly fast. Faster than necessary, and too fast to
    get adequate light to the sensor. But my knowledge and experience are
    still extremely limited.

    Looks like a short focal length. I'm guessing the camera was on a tripod
    and he used a remote to fire? That's another interesting idea to try;
    photographing insects. Right now I find I'm doing a lot of "imitation"
    type stuff for learning exercises. That way I have something to compare
    my photos with.

    Randy.
     
    Randy W. Sims, May 5, 2005
    #6
  7. RichA

    Alan Browne Guest

    Kodak, among others, have a variety of patents on the idea. You can
    mechanize this in different ways, but on these cameras the sensor is
    usually always exposed to the lens (no mechanical shutter). So light is
    always coming onto the sensor. When you hit the shutter release, it
    clears the sensor and then exposes for the set time. One disadvantage
    of this approach is that the sensor is always 'working' and so there is
    more thermal noise. The Oly approach on the 20N appears to be an
    interlaced technique that allows this high speed. (See the Oly site).

    The Nikon D70 also has an electronic shutter for sync flash shots up to
    1/500 (and some people have cleverly bypassed contacts on the flash shoe
    to get much higher electronic shutter speed effects with flash). I wish
    K-M had done this too.

    Gain and adequate light. Don't forget a flash exposure takes place at
    1/500 down to 1/10,000 or even faster regardless of the shutter speed.

    Cheers,
    Alan.
     
    Alan Browne, May 5, 2005
    #7
  8. The encarta sites says 160 to 200 beats per second for a honey bee.

    That means 1/200 of a second to go through a full cycle.

    at 1/500th, the wings would move through 2/5ths of a full cycle.

    To "freeze" the wings you have to have the shutter time well less than
    the time it takes for the wing to move a distance equal to its own
    thickness.

    close examination of the picture might lead one to believe the wingtips
    are just a little more blurry than the rest of the bee which could
    indicate 18000 isn't totally freezing the wings.

    Cool picture though.

    mgg
     
    Michael Gardner, May 5, 2005
    #8
  9. RichA

    jfitz Guest

    With a dedicated flash in automatic, the camera, at least in the case of TTL
    flashes such as those used for the last twenty some years or more by Canon,
    Minolta, Nikon and Olympus, determines and controls the duration of the
    flash, so the camera has this information available to insert in the EXIF
    data.
     
    jfitz, May 6, 2005
    #9

  10. I think it's dead and just stuck on a bit of wire...


    ;)
     
    Craig Marston, May 6, 2005
    #10
  11. RichA

    Alan Browne Guest

    They don't "determine" the length of the flash, they measure the flash
    light returning from the scene and turn off the flash when enough
    exposure is reached. Newer Pre-flash) designs (some film and just about
    all DSLR) pre-determine the amount of flash and set the power of the
    flash. The flash then shuts off after so much power has been delivered
    according to some factory set time limit. (a non linear function
    particular to each flash model).

    It turns out, that in the case of the E-20N in discussion, however, that
    the shutter speed is in fact 1/18,000 (electronic). See other post.

    Cheers,
    Alan.
     
    Alan Browne, May 6, 2005
    #11
  12. RichA

    Paul Furman Guest


    That's a rather wide angle shot. I have been shooting bees and generally
    waited till they land on a flower but this made me want to try. With ISO
    cranked all the way to 1600 on a D70 I could only get to 1/8000 sec:
    <http://www.edgehill.net/1/?SC=go.ph...an-Francisco/our-garden/more/2005-05-05-bees>
    I guess full sun would be somewhat better than bright cloudy weather.
     
    Paul Furman, May 6, 2005
    #12
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