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  1. #1

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    Bellows factors measuring?

    OK guys.. Been out of the loop on shooting these guys for awhile. On bellows factor measuring,. Where do you measure. My camera doesn't have any type of mark to measure from.

    ToddB

  2. #2

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    generally speaking... lens board to film plane/board is sufficiently accurate.

  3. #3

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    I've made up various tape rules with markings for various lenses, calibrated film plane to lens node.
    But it's a lot easier to use one of those little calculator devices from Calumet. You place a target
    at the subject plane and measure its size on the groundglass with a special ruler marked in exposure
    compensation values. I hope they still offer them.

  4. #4

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  5. #5
    SteveR's Avatar
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    Bellows factors measuring?

    I used to use a target thingo, found it a bit fiddly, now I use a simple old sewing tape measure. I've got my lens focal lengths marked along one edge, and D-stops (in inches) along the other edge. Quick and simple to hold it up and see how many stops between the focal length and actual bellows draw. I never used to look forward to calculating bellows factor 'till this little strap came along, can't recommend it enough.
    ____________________________________________

    My goal in life, is to be as good a person as my dog already thinks I am.

  6. #6
    rjbuzzclick's Avatar
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    Quote Originally Posted by SteveR View Post
    I used to use a target thingo, found it a bit fiddly, now I use a simple old sewing tape measure. I've got my lens focal lengths marked along one edge, and D-stops (in inches) along the other edge. Quick and simple to hold it up and see how many stops between the focal length and actual bellows draw. I never used to look forward to calculating bellows factor 'till this little strap came along, can't recommend it enough.
    I do a similar thing with a length of string with a knot every two inches. It's quick and easy.
    Reid

    http://www.flickr.com/photos/rjbuzzclick/

    "If I had a nickel for every time I had to replace a camera battery, I'd be able to get the #@%&$ battery cover off!" -Me

  7. #7

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    I just use a tape measure.
    If I'm using an 8 inch lens (203 Ektar) then at infinity I measure from a point on each standard that are 8 inches apart.
    If I focus on something and the standards are 11 inches apart, measured from the same points, then I know to allow one stop extra exposure.
    At a distance of 16 inches I know to allow two stops extra exposure.
    You can also work in fractions of a stop i.e 9.5 inches or 12.5 inches.
    This also works with my other lenses 101 Ektar = 4 inches, 135 Optar = 5.5 inches etc.
    I don't know if this is accurate enough for colour transparency work but it does well enough for black and white.

    Mike

  8. #8
    SteveR's Avatar
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    Bellows factors measuring?

    Quote Originally Posted by johnielvis View Post
    man, that's cornball style...
    Maybe, but it works every time, plus you don't have to switch into 'left-brain' mode to do the math. It's never steered me wrong, always spot on, plenty of bright colorful chromes testify to its reliability.
    ____________________________________________

    My goal in life, is to be as good a person as my dog already thinks I am.

  9. #9

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    Quote Originally Posted by ToddB View Post
    OK guys.. Been out of the loop on shooting these guys for awhile. On bellows factor measuring,. Where do you measure. My camera doesn't have any type of mark to measure from.

    ToddB

    Ummm.... if you're asking regarding your Rollei, you really don't need to worry. It doesn'f focus close enough for this to be much of a factor, unless you're using chrome film at the closest focussing distances.

  10. #10

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    Ladies and Gentlemen:

    There's a sticky thread on just this topic with more information and techniques than anyone would ever want to know at the top of this forum topic.

    Maybe we should look/post there...

    Just a thought.

    Best,

    Doremus

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