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Thread: Need help focusing in a scene? Critical focusing? Your advice? Technique?

  1. #1

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    Need help focusing in a scene? Critical focusing? Your advice? Technique?

    I have noticed that more often than not my negatives are not in focus as i would like them to be. This is esecially true with my 90mm focal lenght. I beleive it might be my technique that needs refinement. I would love to get some step by step advice on how you critically focus a 4x5 camera, and any tips that might help increase the percentage of keepers in focus. =}

    Thanx in advance.

  2. #2
    Lachlan 717
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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    Perhaps detail your issues in some detail.

    Is it side-to-side focus issues? Front to rear?

    Perhaps post some examples.
    Lachlan.

    You miss 100% of the shots you never take. -- Wayne Gretzky

  3. #3

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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    Anytime you change your movements, check and recheck a few areas of the frame with a good high-power loupe.

    If you're still having problems with static subjects, it may be your camera. Or your loupe. Or your eyesight.

  4. #4

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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    One thing you should do is to make sure your standards are parallel when you are not using tilts or swings. If they aren't parallel, that means you have a slight tilt or swing, so the plane of exact focus won't be parallel to that of the film.

    Here is how I do that. I turn the tripod so that the standards are horizontal. I then put a small bubble level on the ground glass and adjust things so it is level. I then use a level on the front standard to see if it is also level. I sometimes find it is slightly off, and I fix that. I first noticed this with my 75 mm lens. I think it may be more of a problem with shorter focal length lenses.

  5. #5
    kev curry's Avatar
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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    The first thing I would do if you haven't done so already is familiarize yourself with the the article on the home page that explains the ''near far'' method of focusing the view camera.

    http://www.largeformatphotography.info/fstop.html

  6. #6

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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    It would also help if you said what camera you use. They all have their quirks.

  7. #7

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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    Placement of the ground glass relative to the film plane is another possible explanation which would fit with the evidence that it is worse withshorter lenses.

  8. #8
    Drew Bedo's Avatar
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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    "The Ground Glass Is Truth" Before you trip the shutter re-check the GG. Do it wide open if checking the plane of critical fosus. Do it at stopped down if DOF is the issue. when shooting still lifes or table-top compositions I place a focusing target in the scene to help me out. I move it around in the composition if need be to get it right. A bar code palel works pretty well.
    Drew Bedo
    www.quietlightphoto.com
    http://www.artsyhome.com/author/drew-bedo




    There are only three types of mounting flanges; too big, too small and wrong thread!

  9. #9

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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    I think, the problem is getting the focus checked once the lens is stopped down!.. Its gets too dim/grainy... So I beleive I need to learn where to place the "open aperture" focus in order to ensure things will be in focus when stopped down... any suggestions.

  10. #10
    Lachlan 717
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    Re: Need help focusing in a scene? Critical focusing? Your advice? Technique?

    Start with a DOF chart.

    Even if you don't use this in the field, a 5-minute study of the relative depths of field at each f-stop, and the way the DOF is split in front and behind the focal distance, will pay massive dividends.

    Using one in the field will assist you to use the right focal distance to maximise the chances of getting what you want in focus.

    In a short period of time, you'll find that you won't need this chart.
    Lachlan.

    You miss 100% of the shots you never take. -- Wayne Gretzky

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