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Thread: Technique for focusing "into your scene"

  1. #121

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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by AdamD View Post
    So what's this thread about now
    Kansas?

  2. #122
    Drew Wiley
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    Re: Technique for focusing "into your scene"

    Yep. Don't even go there if you haven't practiced tilts first. Don't even come here if you haven't. We have plenty of flat farmland of our own, between the mountain ranges; and much of it is very interesting photographically. Then there are vast deserts areas too. Doesn't get any flatter than a dry Ice Age lakebed. But frozen alpine lakes impose the same depth of field logistics, and I've sure done my share of those.

    With a receding plane, and by approaching it using appropriate tilts, the "scene" you are "focusing into" becomes a continuum. There is no single point at play, like with a fixed position lens and film plane. The whole game actually becomes simplified, once you get accustomed to it.

  3. #123
    Vaughn's Avatar
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    Re: Technique for focusing "into your scene"

    Good point, Michael. Once one gains experience and bends the bellows a few times into a knot, learns what the camera movements can do, and that sort of thing, that experience and knowledge allows one to see possibilities otherwise missed.
    "Landscapes exist in the material world yet soar in the realms of the spirit..." Tsung Ping, 5th Century China

  4. #124
    Alan Klein's Avatar
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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by Michael R View Post
    The diagram is meant to show how objects in those areas could potentially be out of focus even though objects farther away or closer are ok. Here is the same diagram with some objects/areas of your picture very roughly superimposed. Imagine we are looking at the whole setup from the side (to the right of the fence).

    The yellow shaded area is outside the depth of field. You can see therefore that distant parts of the fence would be increasingly blurry. You can also see how the lowest parts of the building facade and the ground in front of it would also be out of focus since they are in the yellow zone (outside depth of field).

    Disclaimer: Please note this is for illustrative purposes only, to show how this sort of artifact might be created. It's an exaggerated picture. There are also variables - how much tilt, points of focus chosen in determining tilt, and of course aperture (which determines how wide or narrow the wedge-shaped depth of field is). And who knows - as Drew noted film flatness is occasionally a wild card.

    As an aside, referring back to Adam's second colour picture (bush), this diagram shows why in his case the railing goes from sharp (at the top) to blurry (at the bottom).

    Different movement choices, chosen points of focus, and aperture can usually solve this type of problem. It takes some practice to get used to it, so don't be discouraged. I understand the initial frustration though. Theoretically this is all discernable on the groundglass (WYSIWYG) but it isn't always easy to see well. This is why in the end most people end up stopping down to at least f/22, usually more, plus "Kentucky windage", even if they think they've nailed it.

    Technically there are formulas for figuring it all out, but good luck with that unless you want to send your surveyor out first.

    Hope this helps.

    Attachment 214642
    Thanks for the diagram. I understand it and it explains the situation well. I have to admit I have trouble seeing it intuitively. I shot it at f22; I suppose f32 would have helped a little.

  5. #125

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    Re: Technique for focusing "into your scene"

    Yes, stopping down more would increase the depth of field "above" and "below" the plane of sharp focus.

    But there are two other choices which might or might not help improve the situation (as I mentioned above). The amount of tilt, and the where you choose to focus, both/each rotate the plane of sharp focus along with that entire depth of field (the area between the red lines). So for example if that wedge was rotated downward a little more, by tilting more or focusing differently or usually a combination of both, the depth of field would include more of the yellow area. Of course you'd have to check to make sure the top of the building was still within the depth of field, maybe decide to stop down more etc. but you get the idea.

    You can see that there is often more than one answer and it involves some judgement (in addition to checking things on the groundglass). You can also see that while you can "optimize" to some extent, it's still a compromise. For example, suppose you really wanted the building in perfect or near-uniform focus. You might decide to focus on the building, use less tilt, or no tilt etc. (I could do another diagram if you want).

    The point is with practice/repetition this becomes a more intuitive process - as both Drew and Vaughn can vouch for. It will become more "routine" when you stand before a scene, to decide what to use as your near/far points of focus when figuring out your tilt or swing (and sometimes you'll find you're better off not tilting/swinging), choose your aperture etc.



    Quote Originally Posted by Alan Klein View Post
    Thanks for the diagram. I understand it and it explains the situation well. I have to admit I have trouble seeing it intuitively. I shot it at f22; I suppose f32 would have helped a little.

  6. #126

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    Re: Technique for focusing "into your scene"

    I have many 30x40 prints from various commercial scans, and the detail and quality output with apertures between f32 nd f45 is incredible, assuming I have implemented proper technique otherwise. Especially with LF, I don't concern myself with diffraction, but obtaining the shot envisioned. So most of my images end at somewhere around F45 (as insurance). Taking more than one image at different F stops allows you the flexibility of throwing out the one which has insufficient DOF. For color chromes, obtaining correct exposure is key since these films have very little latitude. In those cases I will also vary exposures with different sheets to ensure I have a good one.

    BTW Alan, check out Franklin Parker Preserve in SC New Jersey as a possible sight for image taking. Via Chatsworth. I just happened upon it venturing the net for Pine Barrens bog sites. I am considering it for my trip in early July.

    PD

  7. #127

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    Re: Technique for focusing "into your scene"

    P.S. I am reminded of both Stella Johnson and Sebastiao Salgado, for example, both of whom used Leicas and would stop down the lens well into diffraction territory to get as much in focus as possible. Many of their images are indelibly imprinted in my mind.

  8. #128
    Alan Klein's Avatar
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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by pdmoylan View Post
    I have many 30x40 prints from various commercial scans, and the detail and quality output with apertures between f32 nd f45 is incredible, assuming I have implemented proper technique otherwise. Especially with LF, I don't concern myself with diffraction, but obtaining the shot envisioned. So most of my images end at somewhere around F45 (as insurance). Taking more than one image at different F stops allows you the flexibility of throwing out the one which has insufficient DOF. For color chromes, obtaining correct exposure is key since these films have very little latitude. In those cases I will also vary exposures with different sheets to ensure I have a good one.

    BTW Alan, check out Franklin Parker Preserve in SC New Jersey as a possible sight for image taking. Via Chatsworth. I just happened upon it venturing the net for Pine Barrens bog sites. I am considering it for my trip in early July.

    PD
    Thanks That's about an hour south from my home.

  9. #129
    Alan Klein's Avatar
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    Re: Technique for focusing "into your scene"

    Quote Originally Posted by pdmoylan View Post
    P.S. I am reminded of both Stella Johnson and Sebastiao Salgado, for example, both of whom used Leicas and would stop down the lens well into diffraction territory to get as much in focus as possible. Many of their images are indelibly imprinted in my mind.
    When I staterd shooting 35 years ago with my RB67 medium format, I read and then followed this advice I read about. Seems to work. I'd calculate the DOF I need. Then stop down one more stop for good measure.

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