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Thread: Process lens image circle nature

  1. #11

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    Re: Process lens image circle nature

    Quote Originally Posted by erian View Post
    I am planning to buy my first large process lens and I am wondering how does various process lenses image circle behave. Is it quick cut off or more gradual fade?

    I am considering something around 750-800mm range and I plan to use it for portraiture (i.e. 1:1).
    My LOMO O-2 600mm, a dyalite type, covers 41º in the specs but it illuminates around 90º, with increasing softness when going beyond the specified coverage circle.

    Illumination circle of APO-Nikkors are also reportedly very big: https://www.largeformatphotography.i...ll=1#post56941

    So for your application they may work, as you may have the corners in the out of focus, still you will have fall-off in the outer illumination boundary.

  2. #12
    Vaughn's Avatar
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    Re: Process lens image circle nature

    Quote Originally Posted by erian View Post
    I plan to build a camera obscura. The one where you can walk in. I plan to focus by moving the back inside the camera. I am thinking to use large photo paper and by large I mean really large like 1 meter by 60 cm or similar.
    Cool! Vacuum frame? That would also be cool, but a bit of extra work. Have fun!
    "Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China

  3. #13

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    Re: Process lens image circle nature

    Quote Originally Posted by Pere Casals View Post
    My LOMO O-2 600mm, a dyalite type, covers 41º in the specs but it illuminates around 90º, with increasing softness when going beyond the specified coverage circle.

    Illumination circle of APO-Nikkors are also reportedly very big: https://www.largeformatphotography.i...ll=1#post56941

    So for your application they may work, as you may have the corners in the out of focus, still you will have fall-off in the outer illumination boundary.
    Nice, this is exactly what I was looking for.

    Does anybody know this about Ronars and Artars?

  4. #14

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    Re: Process lens image circle nature

    Quote Originally Posted by Vaughn View Post
    Cool! Vacuum frame? That would also be cool, but a bit of extra work. Have fun!
    I thought about this on my way home today. How to keep vertical junk of paper flat. Yes, vacuum would do put I thought that it definitely will not fit into thigh time frame. I have about a week to build and use this (in addition to other Christmas activities).

  5. #15
    Tin Can's Avatar
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    Re: Process lens image circle nature

    One week!
    ,
    Use what you got, no vacuum, tape it up, use longest LF lens you have, use a hat for a shutter as paper is very low ISO, like 2 to 5 ASA which is the same almost as ISO.

    If it's a family pic, do it after they all fall asleep and are not moving. The exposure may be very long.

    No lens, use a pinhole and even longer exposure, Go here, https://www.mrpinhole.com/

    Post the results here no matter what it looks like.

    Repeat yearly.

    Merry Christmas!

    Out

    Quote Originally Posted by erian View Post
    I thought about this on my way home today. How to keep vertical junk of paper flat. Yes, vacuum would do put I thought that it definitely will not fit into thigh time frame. I have about a week to build and use this (in addition to other Christmas activities).
    Tin Can

  6. #16

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    Re: Process lens image circle nature

    Quote Originally Posted by erian View Post
    I thought about this on my way home today. How to keep vertical junk of paper flat. Yes, vacuum would do put I thought that it definitely will not fit into thigh time frame. I have about a week to build and use this (in addition to other Christmas activities).
    For a temporary camera, I'd just use low stick spray adhesive on the back of the paper.

  7. #17

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    Re: Process lens image circle nature

    Quote Originally Posted by erian View Post
    this about Ronars and Artars?
    Ronars and Artars are also dyalites, with similar behaviour.

  8. #18

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    Re: Process lens image circle nature

    Quote Originally Posted by Pere Casals View Post
    Ronars and Artars are also dyalites, with similar behaviour.
    How about Apo Gerogons?

  9. #19

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    Re: Process lens image circle nature

    Quote Originally Posted by Bob Salomon View Post
    How about Apo Gerogons?
    If you'd read this discussion from the beginning you'd know that the longest Apo-Gerogon is too short for the OP's project.

  10. #20

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    Re: Process lens image circle nature

    Quote Originally Posted by Pere Casals View Post
    Ronars and Artars are also dyalites, with similar behaviour.
    There are dialyte type Apo-Nikkors, too.

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