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  1. #31
    Diapositivo's Avatar
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    Mark, I said in my post #20 "while using small format".

    What you say, if I get it right, is a way to obtain the entire façade, or set of lines, "vertical" on the frame by using "movements".

    What I am talking about is a simple rule to judge when the camera is perfectly levelled in presence of a subject which is not necessarily parallel to the focal plane with a camera pointed upward and which has no movements.

    The property acutely observed and illustrated by Dan in post #26, and which is in fact common to every ground glass with some sort of checkers pattern , is - in those conditions - not shared by the lines on the resulting image, because of the perspective convergence of lines (absent "movements").

    PS I perfectly know that one can use shift lenses also on 135 format. I bought a camera on purpose to use it with my two shift lenses. What I am talking about is how to deal with perspective, not how to cheat with it
    Last edited by Diapositivo; 08-28-2012 at 05:40 PM. Click to view previous post history.
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
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  2. #32
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    Quote Originally Posted by markbarendt View Post
    If you want all the verticals and all the horizontals square, the film plane needs to be oriented absolutely parallel to the subject plane.
    That's correct.

    Accurately assessing that condition may or may not be simple.

    - Leigh
    “Wise men talk because they have something to say; fools, because they have to say something.” - Plato

  3. #33
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    Fabrizio,

    The physics remains the same regardless of the lens or format.

    The only thing that matters is the relationship of the film plane and the subject plane, they must be parallel.

    There are certain tricks that can be used to get darn close with a fixed lens camera, for example if I'm on level ground and my camera is head high then placing someone's head in the view finder half way between top and bottom (anywhere from right to left) essentially levels the camera for pitch and the verticals will be darn close to right with just that and leveling to the horizon or a building edge anywhere in the frame for right left tilt. That only deals with the verticals though. You then have to pan to get the horizontals.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  4. #34
    tih
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    Mark,

    I think you're reading too much into what Fabrizio is saying.

    Quote Originally Posted by markbarendt View Post
    There are certain tricks that can be used to get darn close with a fixed lens camera, for example if I'm on level ground and my camera is head high then placing someone's head in the view finder half way between top and bottom (anywhere from right to left) essentially levels the camera for pitch and the verticals will be darn close to right with just that and leveling to the horizon or a building edge anywhere in the frame for right left tilt. That only deals with the verticals though. You then have to pan to get the horizontals.
    Correct, of course - but not the situation he was talking about.

    All Fabrizio really claimed was that if you're deliberately not leveling the camera for pitch, and you have real verticals in the frame, such as building edges, then you can level the camera horizontally by making a real vertical in the center of the frame appear vertical on the ground glass - but it has to be in the center of the frame for it to work.

    In other words: if the camera is on a tripod, and the tripod head is perfectly leveled, and then pitched up, panning it across the building will show each vertical on the building vertical on the ground glass when (and only when) it is exactly in the middle of the frame.

    -tih

  5. #35
    Diapositivo's Avatar
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    Exactly.

    But what I also meant to say more specifically is that "leveling" the camera or the tripod is a tricky exercise as there often remains a 0.2° mistake or so. The proof being ultimately in the pudding, what you do is to take the picture with your "levelled" camera and than check the "verticality" of a line in the centre of the frame, if any, to check that the image is actually horizontal.

    Mark insists that I should only take pictures with the façade parallel to the focal plane! . I don't contest the correctness of his explanation of camera movements, I just gave a simple rule for knowing when a photo is correctly levelled "in the field", which - very importantly - can be applied also after the fact.

    What one does after capture is rotate the image so as to eliminate that small 0.2° mistake which is easily there and which you really notice only after you redressed the problem. When the frame is perfectly levelled there is something snapping into place and you can almost hear the "click" ...

    Rotating the image: those using a hybrid method will "rotate the canvas", those using an enlarger will I suppose either use some sort of film holder with lines to align the paper under the image or reframe the image with an enlarging easel.

    And lest somebody says that art should be free and that my concept of art is limited I would also like to say that I do have a preference for correctly levelled images especially when the horizon or the ground is visible, but I might disregard horizontality sometimes, especially when the horizon or the ground are not visible (my "avatar" image is not levelled, as an example).
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
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  6. #36
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    Quote Originally Posted by Diapositivo View Post
    Mark insists that I should only take pictures with the façade parallel to the focal plane! .
    Actually I'm not insisting or even suggesting that anyone shoot that way.

    Mark is simply suggesting that math, including geometry, is a science.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  7. #37
    Diapositivo's Avatar
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    Mark I agree geometry is a science. Is there anything wrong in what I wrote?

    I still maintain that your quotation of mine in post #28, in which you said I was wrong, it is instead right.

    If a vertical line, which is vertical in reality, is also vertical in the centre of the viewfinder, the camera is horizontal regardless of the orientation of the subject and regardless of the relation between object plane and camera plane.

    I still maintain that until proven wrong on the field of science.
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
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  8. #38
    markbarendt's Avatar
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    Yes, you really are wrong in that case.

    Format makes no difference, and leaving aside lens distortions/imperfections for clarity, any camera that is properly leveled so that the film Plane is vertical will render all verticals in the composition correctly, not just the one in the middle.
    Last edited by markbarendt; 08-29-2012 at 07:39 AM. Click to view previous post history. Reason: Grammer
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

  9. #39
    Diapositivo's Avatar
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    Quote Originally Posted by markbarendt View Post
    Yes, you really are wrong in that case.

    Format makes no difference, and leaving aside lens distortions/imperfections for clarity, any camera that is properly leveled so that the film Plane is vertical will render all verticals in the composition correctly, not just the one in the middle.
    Aaarrgghhh!

    I have already specified that I cited 135 as it has no movements of his own

    A camera can be levelled along three axis but when we say "levelled" we mean "horizontal" parallel to the ground! A camera can be and is horizontal (on that plane) also if the film plane is not vertical!

    The rule, which is absolutely right unless you have some decent argument to propose against it, is that if a line, which is vertical in reality, is vertical in the CENTRE of the screen, then the camera is properly HORIZONTAL (levelled). That is true even if the film plane is not vertical, and even if the subject "plane" is not parallel to the film plane. It's a rule that always works.

    I NEVER said that if a line, which is vertical in reality, is vertical in the CENTRE of the screen then the film plane is vertical!

    The film plane is in my examples NOT vertical because as I stated too many times the camera is pointing upward which creates convergence of all lines toward some vanishing points somewhere!

    And I am BLOODY RIGHT on that Please read carefully before expressing scientific truths in the wrong context.

    How tiring!
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
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  10. #40
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    Quote Originally Posted by Diapositivo View Post
    Aaarrgghhh!

    I have already specified that I cited 135 as it has no movements of his own

    A camera can be levelled along three axis but when we say "levelled" we mean "horizontal" parallel to the ground! A camera can be and is horizontal (on that plane) also if the film plane is not vertical!

    The rule, which is absolutely right unless you have some decent argument to propose against it, is that if a line, which is vertical in reality, is vertical in the CENTRE of the screen, then the camera is properly HORIZONTAL (levelled). That is true even if the film plane is not vertical, and even if the subject "plane" is not parallel to the film plane. It's a rule that always works.

    I NEVER said that if a line, which is vertical in reality, is vertical in the CENTRE of the screen then the film plane is vertical!

    The film plane is in my examples NOT vertical because as I stated too many times the camera is pointing upward which creates convergence of all lines toward some vanishing points somewhere!

    And I am BLOODY RIGHT on that Please read carefully before expressing scientific truths in the wrong context.

    How tiring!
    Ok, let's try a little context. You led the thread off topic. This thread was started to discuss leveling a field camera, one with movements.

    If you want to discuss leveling cameras without movements and the compromises you might want make, it might be courteous to start a thread along those lines instead of muddying up the discussion here.

    Also, it is possible that I missed it, but the first reference that I saw that you acknowledge tilting the camera Up is in your response to tih in #35.
    Mark Barendt, Ignacio, CO

    "We do not see things the way they are. We see things the way we are." Anaïs Nin

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