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  1. #51
    Diapositivo's Avatar
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    Quote Originally Posted by Steve Smith View Post
    Is shutter bounce a known reality or is it just a bit of mythology?

    I can't really see how a leaf shutter could open again before closing.


    Steve.
    Imagine two cars going at very high speed against each other frontally. When they crash, at least one of those will bounce backward. A physician, which I am not, could maybe say that they bounce when the kinetic energy they have is superior to the one which can be absorbed by the deformation of the other car.

    In the case of the shutter it could be a bit like a window which is banged by an air current against the frame. Although the energy is impressed only in one direction, toward the frame, the window will "bounce" on the frame.

    Now imagine a spring impressing a motion on the window. The window will reach a certain speed, bang on the frame, and if the spring (in extended position) is not strong enough, the window will bounce back, immediately after the spring will push it again against the frame.

    Another example would be a marble ball "bouncing" over a marble floor although marble is not elastic.
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
    Stock images at Imagebroker: http://www.imagebroker.com/#/search/ib_fbr

  2. #52
    JBrunner's Avatar
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    Note to self- Photograph trains while stopped.

  3. #53
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    Shutter bounce. The 'nose' under the numbers shows a faint double image also, demonstrating that it is not only the number plate showing the effect. It is true that the number plate was not present on the locomotive in 2003, but I suspect it would have fallen off by now if not bolted down tight

    Here is an example of shutter bounce. You can see how this second shutter opening would make the second faint image of the numbers:
    Click image for larger version. 

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    Read more about it here http://www.mraggett.co.uk/shuttertester/

  4. #54
    Paul Goutiere's Avatar
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    Quote Originally Posted by Steve Smith View Post
    Is shutter bounce a known reality or is it just a bit of mythology?

    I can't really see how a leaf shutter could open again before closing.


    Steve.
    I don't see how either. A focal plane shutter yes, but I've never heard of a leaf shutter with this problem.

    Someone enlighten me.

  5. #55

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    Quote Originally Posted by johnielvis View Post
    Something's moving and it ain't the train--it's the film. I've had this happen to me doing multiple pops of flash...film will move when it adjusts to the atmosphere--particularly when the atmosphere changes rapidly like when pulling a darkslide--larger film can pop and bubble in some places and be constrained in others from the back of the film holder.

    so you do have something very light (the film) with a comparatively large force acting on it--thermal stress...or suddenly unbalanced gravity forces---all of these must reach equilibrium before the film stops moving--sometimes the film shifts and pops in certain places very quickly--you opened the shutter while the film was in mid pop---this happens ALL THE TIME when enlarging negatives. The bigger the film, the bigger the forces and the longer it takes for film to settle. You'll see this a lot more often with bigger formats--it's almost nonexistent with 4x5 and impossible with pressure plate roll films.

    so you had exposure beginning--film in unstable position and not moving but unstable....exposure progresses part way and film suddenly pops (thermal stress? pressures front and back suddenly becoming balanced? nudge from shutter vibration?--whatever) film moves quickly and again becomes still in another position for the remainder of the exposure. If the train were moving you would not have a clear double image like that and it would be smear image all over for everything on the train...it would look like a classic shutter speed being too slow to freeze the action.

    double image indicates exposure in one position--negligibly quick motion to another position, and then exposure in a second position.
    Thanks for the reply but that is the one thing I know didn't happen as once I had set the camera up where I wanted it and focused I had inserted the film holder and then removed the darkslide and waited for the next train to arrive which was some 30 minutes later. During this time and also during the exposure my blackjacket was draped over the camera with the shiny side up to reflect any sun that might fall on it, not that there was much around that day.

  6. #56
    Diapositivo's Avatar
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    The train vibration might have caused the film to change "state". The "film pop" explanation seems valid to me.
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
    Stock images at Imagebroker: http://www.imagebroker.com/#/search/ib_fbr

  7. #57
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    Quote Originally Posted by jeffreyg View Post
    Was the number that was painted on the plate repainted but not in the same registration?
    I am late to the party, but I believe the below picture that I found on Flickr dispels the repainted off registration theory...however the photo below was taken 9/17/11, possible, but seems implausible to me:

    http://farm7.staticflickr.com/6214/6...2c616d48_z.jpg
    Andy

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