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Thread: f64

  1. #1

    Join Date
    Oct 2005
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    f64

    I have heard plenty of trash talk about the resolution of large camera lenses over the past few years. I have also heard that one should never close all the way down.

    Well, I've just done the test for myself and I say its not true - at least for me - in the least. I pointed the camera out my front door and closed it down to f64. (I love depth of field.)

    Now maybe some others want more sharpness than this example, but I am perfectly satisfied.... It's straight off the scanner, with no sharpening at all....

    Saving for web made it way darker than I am going to print it, but take a look, and judge for yourself. I know I'm going to use f45 and f64 any time I want from now on, without fear that I'm losing something.

    http://eigerstudios.com/sharpness64.html

    Lenny
    EigerStudios

  2. #2

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    Re: f64

    I stop way down always, rarely less than f45. I'll take the depth of field and image circle I get with my wide lenses at f64 any time.

    Not sure what I may be missing out on, don't care.

    www.timeandlight.com

  3. #3
    Vaughn's Avatar
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    Re: f64

    If I have to choose between areas out of focus or perhaps a slight loss of sharpness, I'll take the latter. And it is nice to use process that one can only contact print with.

    When enlarging to 16x20 from 4x5, using f16 did get me sharper prints than negatives taken at f64 (Caltar II-N 150/5.6).

    Vaughn

  4. #4
    Drew Wiley
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    Re: f64

    It's simply a scientific FACT that diffraction affects sharpness at very small apertures. But everything obviously depends on the degree of print magnification
    and everything else inbetween, and also on the precision of the film plane in the first place (ordinary filmholders don't hold film completely flat). In terms of personal technique, I generally stop down 4x5 lenses to f/22 to f/32 for the best combination of sharpness and depth of field, and 8x1O lenses from f/32 to f/64 - between these, it would be hard to note the difference in a 20X24 print, but distinctly noticeable in a 30X40 or 40X60 optical enlargement. Digital output is a little less fussy, since it can't resolve as much fine detail. Once again, I don't believe any of that "normal viewing
    distance" bullshit - I'm referring to actual detail.

  5. #5
    Drew Wiley
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    Re: f64

    Well, I just looked at your actual images, Lenny - the size of a postcard, and on the
    web a ball of fuzz that could have been taken with a pocket point n' shoot with vaseline over the lens. Sorry to be sarcastic, but this kind of presentation proves zero with respect to either large format technique or the quality of current lenses.

  6. #6

    Join Date
    Nov 2010
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    665

    Re: f64

    DOF is like taxes, you only stop down to obtain the required circle of confusion, and with taxes pay no more than necessary. With skill, you learn to maximize hyperfocal point, use movements carefully and therefore use f-stops < f64; and one finds legitimate ways to reduce their tax burden. There are times when f64, with all the skill you have, is still necessary. William Neill would commonly stop down to F64 and Dykinga would shoot at F45 and beyond with many challenging images where maximum DOF is required. In such cases, ultimate sharpness (visual acuity) is less important than obtaining the results you need. I find that using mild wide angles on 4x5 (75mm - 110)with a foreground object that is very close to the lens while trying to obtain focus on it and the distant landscape is the time employ beyond f45.

  7. #7

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    Re: f64

    Lenny,

    I have done comparison shots of the same set up. I find that seeing the loss at really small apertures requires some high frequency data in the pictures. Blades of grass, really small branches, that sort of things. Without that, it is hard to see a difference. Without a direct comparison, it would be hard to see any difference at all, at least with very sharp lenses. I also use whatever is necessary for sharpness demanded by the composition. I am trying to use more limited DOF and stop worrying about about overall sharpness.

  8. #8
    Peter De Smidt's Avatar
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    Re: f64

    I usually prefer overall focus with my LF images over maximum sharpness, and so I wouldn't hesitate to us f64 if needed. But I don't make very big prints. If you'd like to, you might want to check out focus stacking.
    “You often feel tired, not because you've done too much, but because you've done too little of what sparks a light in you.”
    ― Alexander Den Heijer, Nothing You Don't Already Know

  9. #9

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    Re: f64

    A perfectly good eyeball can only resolve 5 lpmm at normal viewing distance.

    So defraction kicks resolution from 50 lpmm to 20 lpmm,

    so what, a 4x enlargement still looks tack sharp.

    So with an 8x10, you can still make a very large print.

    Bob

  10. #10
    Resident Heretic Bruce Watson's Avatar
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    Re: f64

    I think it was Miss Manners who said something along the lines of: It's important to understand the rules so you can have fun breaking them.

    In LF, I think it's important to understand how it all works, including diffraction. That way you can make intelligent and informed decisions during setup. It's all a tradeoff. Knowing what you are trading for what, and how much, can be the difference between good and excellent photographs.

    That said, I often trade off some sharpness to get more DOF. And sometimes I'll accept more sharpness to get *less* DOF. It all depends on what I want to capture at the time.

    Bruce Watson

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