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Thread: Minimum f-stop?

  1. #1
    Jeremy D
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    Minimum f-stop?

    I read that LF photography is often performed at very small apertures. Seems like anywhere from f/22 to f/64 is frequently cited. But in practice, what do you use? For stills? Portraits? Landscapes?

    I am new at LF photography, so I thought I would just try a comparison. Here's a hat of mine, first at f/5.6, then f/8. DOF is shallow, especially at f/5.6

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    The first doesn't really seem usable, but by f/8, things look better, and the DOF could be quite useful, depending on the situation.

    So, again, in practice, what f-stops do you find that you use the most. Do you ever shoot wide open?

  2. #2
    C. D. Keth's Avatar
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    Re: Minimum f-stop?

    Quote Originally Posted by Lffbug View Post
    I read that LF photography is often performed at very small apertures. Seems like anywhere from f/22 to f/64 is frequently cited. But in practice, what do you use?
    f/16 to f/64. Most commonly my pictures are at f/22, probably followed by f/45 and f/16 in that order.



    Quote Originally Posted by Lffbug View Post
    Do you ever shoot wide open?
    Very, very rarely. Even portraits I prefer to be in the f/8 to f/11 realm.
    -Chris

  3. #3
    Lachlan 717
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    Re: Minimum f-stop?

    Seems to me that you have the tail wagging the dog by asking what we use.

    I think you'll get a much better explanation of DoF by explaining what you're trying to do. Or, put a different way, what you have pre-visualised.

    If your questions are as basic as what do you use for landscapes and what do you use for portraits, well, you generally use small apertures for the former and large for the latter. No different to any other format.

    But, I suspect that you want to know something different to that...
    Lachlan.

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

  4. #4

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    Re: Minimum f-stop?

    Most large format lenses are diffraction limited at f22. Some at f11. Go beyond these stops you will degrade the image from diffraction.

  5. #5
    Land-Scapegrace Heroique's Avatar
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    Re: Minimum f-stop?

    My personal experience w/ landscapes...

    Using movements, I can bring the elements of most of my landscape shots into focus and use what is normally considered the optimal aperture for most LF lenses – f/22.

    But in most situations, the 4x5 photographer can go one, two, three “clicks” narrower and not worry about diffraction.

    For even strict standards for coc in prints up to around 16x20 will allow one to use f/45 without generating discernable diffraction. And if the print is smaller, the aperture can be narrower. Sure, diffraction is “setting in” on a theoretic level as you click down from f/22 to f/32 to f/45 and narrower, but to a degree that a field photographer can often ignore, so that more critical issues can be addressed – like performing magic tricks to make the wind subside.

  6. #6

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    Re: Minimum f-stop?

    Whatever works for subject and picture, light and composition. Whatever dictated by distance, lens itself and plan.

    With LF you can just close and inspect..

    Whole lot of people are after LF for shallow DOF. Thus your mileage might vary.

  7. #7

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    Re: Minimum f-stop?

    Quote Originally Posted by Lffbug View Post
    I read that LF photography is often performed at very small apertures. Seems like anywhere from f/22 to f/64 is frequently cited.
    Isn't the whole point of tilt and swing so one doesn't have to shoot at such a small aperture?????

  8. #8

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    Re: Minimum f-stop?

    The basic rule of thumb which I follow is to use the camera movements to place the plane of focus where I want it, as accurately as possible. I then stop the lens down until the DOF is adequate. Obviously, this rule cannot be followed in every case, there are times when you simply cannot get everything you want sharp, sharp. The laws of physics don't allow it.
    I try to use f:16 to f:22 as my standard apertures, for general subjects. Portraits can be done wide open, the residual spherical aberrations in some of the lenses I use then give a nice glow with a sharp core.

    If you take the time to learn and understand the functions of movements and DOF, you will have no trouble choosing the appropriate aperture for a given situation. It's a learning curve, and it takes time and practice.
    You don't have to use up film, though, you can set up still lifes on a table top and just practice focussing on the groundglass. This is where a good loupe and an effective darkcloth become important - if you cannot see the image on the GG clearly, you won't know what you have until you see the film - which situation sometimes entails a great waste of film. Have patience, and practice!
    One man's Mede is another man's Persian.

  9. #9

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    Re: Minimum f-stop?

    Quote Originally Posted by C_Remington View Post
    Isn't the whole point of tilt and swing so one doesn't have to shoot at such a small aperture?????
    C, the movements are used to correct perspective distortion and place the plane of focus where you want it.Simply stopping the lens down to extend DOF will still leave you with a plane of focus parallel to the film, and will do nothing for perspective distortion.
    One man's Mede is another man's Persian.

  10. #10

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    Re: Minimum f-stop?

    IMHO (and the opinion of many others here based on previous posts about this subject) diffraction is essentially a non-issue with 4x5 film and prints in the range of maybe 20x30 or smaller (I'm guessing about maximum size here, it may very well be even larger than 20x30 but I've never printed that large from a negative made with a very small aperture - I do know from experience that my 16x20 prints show no effects of diffraction from negatives made even at f/64). IMHO far more photographs are ruined by inadequate depth of field when the photographer was overly concerned about diffraction and so didn't use a small enough aperture than have ever been ruined by diffraction when using LF film.
    Brian Ellis
    Before you criticize someone, walk a mile in their shoes. That way when you do criticize them you'll be
    a mile away and you'll have their shoes.

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