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Thread: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

  1. #1

    Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    Asking for some technical help please. This attached scan is a partial crop of an 8x10 negative. I am finding difficulty achieving sharpness throughout the image. The plane of focus I selected seems to run from the front of the golf clubs up through the top front of the golf bag. The golf shafts are quite soft. Is it possible to get everything sharp? The lens was pretty close to the subject with the camera tilted down plus front tilt and aperture around f22. My camera has front and rear base tilts plus front and back swing. The lens is a Fujinon 210mm f5.6.Click image for larger version. 

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  2. #2

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    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    Michael,

    What do you want to be sharp?

    I assume the question, "is it possible to get everything sharp? in this case means everything in this particular crop. Yes?

    If so, the plane of focus rises too steeply from the near edge of the clubs to the front edge of the bag. It may actually be rising even more steeply than that and the front edge of the bag is in focus only because it is within the acceptable DOF below the plane.

    With the plane of focus tilted, the depth of field extends above and below the plane of focus and, of course is controlled by the f/stop number. In this case the DOF is quite thin and the shaft of the clubs lies too far below it.

    You'll do better letting the plane drop lower toward the rear. You can empirically adjust the tilt by examining the image on the ground glass. At least 3 iterations of tilt/adjust focus/tilt are needed. Or you can adjust it precisely in one effort using Howard Merklinger's tables.

    Rich

  3. #3
    ic-racer's Avatar
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    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    Smaller format. In my work, the only reason to use large format for closeup is the shallow DOF you can't get any other way.

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    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    Adjustments are helpful when the subject is basically 2-dimensional, but they can't work miracles.

    A 210mm lens at f/22 has the same depth of field as a 105mm lens at f/11, a 50mm lens at f/5.6, etc: not a great deal.

    Try stopping the lens down to f/128 or as far as it will go. This will help bring the rest of the image into focus.

    On 8x10, 210mm is a wide-angle lens. Close shots will likely exhibit foreshortening.

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    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    I'd use an 8 1/4" Dagor at f/45-64, or perhaps a bit longer Dagor.

    L

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    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    Rich 14 has your answer. You should place your plane of sharp focus so that it splits the distance between points that you want to keep in the zone of sharp focus.

    Keep in mind that when you tilt the plane of sharp focus aggressively, like you are doing, the area "behind" the plane is now below it, and vice-versa. Check your focus spread by tilting and then checking points above and below the plane of focus that you want sharp. The optimum tilt will have the minimum distance between focus points; the actual distance between focus points on the rail or bed can be used to find an optimum f-stop. See here: http://www.largeformatphotography.info/fstop.html .

    FWIW, f/22 is likely way to wide for what you're trying to do. I'd be starting with f/45 on 8x10...

    Best,

    Doremus

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    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    Without starting a war, as usually happens in these type of discussions -

    DOF has nothing to do with the format (4x5 vs 8x10). It's not more shallow for the larger format. It has nothing to do with lens focal length.

    DOF depends on aperture and magnification of the image relative to the size of the subject.

    If any camera (from cell phone on up to 5x7) and an 8x10 are both set up to have the same perspective of the subject, using any lens (as long as it can get the image onto the film) set to the same f/stop, the resulting images will have the same DOF if they are printed to the same size. They will look identical except for the higher IQ from the larger format. (That's simple physics)

    Of course, an 8x10 image on the negative will have less DOF that the image from the smaller camera on its negative. But that's irrelevant. That's not producing the images to the same size. Nor is making contact prints from those negatives.

    As an extreme example, a small camera using a wide angle lens and an 8x10 using a longer than normal lens will produce images with the same DOF if the lenses are set to the same f/stop and the images are printed to the same size.

  8. #8
    ic-racer's Avatar
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    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    In this setting, the shallow DOF is a result of the high magnification needed to fill a large format negative.

  9. #9

    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    I could shoot 4x5 IC Racer using a home-made reducing back so my subject size fills more of the frame, but that ain't 8x10 is it.
    I want to shoot closer with the 8x10 so will have to rethink composition and subject matter. Oh well. Michael

  10. #10

    Re: Help Wanted for Close Up Plane of Focus and Sharpness on an 8x10

    Thanks Rich 14 - I probably didn't understand my own question to make it more clear. To lower my plane of focus do I select a focus point further down into the image, use tilts and swings and then step down? Cheers Michael

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