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  1. #21

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    Very curious - some places are sharp and others not. I notice some lack of sharpness in the foliage on the left as well, and I wonder if it might be the same thing. The number plate shows two distinct, sharp images, which pretty mush rules out motion blur. A reflection is one possibility. Another is that the film was not perfectly flat in the holder, and it "popped" during the exposure.

  2. #22

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    Please forget about the numbers, it's incidental. The whole front of the train is blurred. Please look at the highest res version.

    The shutter speed used is only adequate for the time it takes for the first carriage to exit the frame. Say 3 seconds.
    The front of the train would exit the frame in a fraction of that, so the shutter speed needs to be increased to freeze the front of the train - which is moving through the frame faster than the rest of it.

    The apparent differences in speed of parts of the train is an effect of the converging perspective or vanishing point.

    Quote Originally Posted by Hatchetman View Post
    It is image speed across the film plane we are worried about.
    Thanks for mentioning that. Solved.
    Last edited by batwister; 08-27-2012 at 11:33 AM. Click to view previous post history.

  3. #23

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    Number plate was not secure.

    Film moved from humidity.

    Reflection off back of holder.

    Got it. faint image is what is recorded during the shutter close to full open time. The darker, more neg density, image is what is recorded during the full open part of the exposure which is longer. Leaf shutters have three components, close to open, open, then open to close. Depending on shutter speed, these three components are different percentages of the shutter speed. The dark areas have too little intensity to record during the opening and closing phases.

    Changed my mind, the faint image was during the closing phase when there was enough "pre-exposure" to partially excite the silver.
    '
    Last edited by Ronald Moravec; 08-27-2012 at 11:25 AM. Click to view previous post history.

  4. #24
    DWThomas's Avatar
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    Loose lens mount or lens board? Yeah, pretty far out, but thought I'd toss it in. I agree that the two sharp extremes of position, most obvious in the numbers, is a bit odd; I would expect more of a smear from just plain motion blur. Years ago I shot some rail stuff with hand held 4x5 and panned with the subject of interest; that appeared to work, but I doubt I ever examined the results this closely.

  5. #25
    Jim Jones's Avatar
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    Shutter bounce? More likely with focal plane shutters than the shutter in a lens, though.

  6. #26

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    Thank you all for your thoughts, I don't know which is correct though, shutter bounce seems plausible, perhaps I need to just be further away, many large format lenses don't have shutters that go higher than 1/250th sec, more so with the longer lenses in larger shutters.

  7. #27

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    Quote Originally Posted by Ed Bray View Post
    Thank you all for your thoughts, I don't know which is correct though, shutter bounce seems plausible, perhaps I need to just be further away, many large format lenses don't have shutters that go higher than 1/250th sec, more so with the longer lenses in larger shutters.
    Hopefully this diagram explains what I was saying a little clearer.

    http://2.bp.blogspot.com/-98IUJsPLNR...terdiagram.jpg
    Last edited by batwister; 08-27-2012 at 12:01 PM. Click to view previous post history.

  8. #28
    Ian Grant's Avatar
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    Quote Originally Posted by batwister View Post
    Hopefully this diagram explains what I was saying a little clearer.

    http://2.bp.blogspot.com/-eqVlsem_JC...terdiagram.jpg
    Totally agree, this kind of blur is quite nornal with shots like this. 1/250th isn't always fast enough.

    Ian

  9. #29
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    Question: are/were there faster shutter speeds available for large format? I'm curious as to how the train photogs of the 30s and 40s accomplished such striking photos of steam trains at speed. Maybe they aren't actually as sharp as they appear at first glance. Guess I never really thought of it...

  10. #30

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    The fastest shutter speeds on my Copal/Synchro Compur 0 & 1s is 1/400 or 1/500 but on my Compur 3s it is 1/200 sec

    I can only assume that sharp images from ages old shot on large format were shot further away with longer lenses and then cropped perhaps?

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