How often do you calculate the depth of field

  • 39 votes.
  • Started by TomAxford on June 14, 2023.
Often
3 votes, 8% of total.
  • 3 votes, 8% of total.
Sometimes
8 votes, 21% of total.
  • 8 votes, 21% of total.
Never (I rely on experience, or depth of field preview, or trial and error, ...)
28 votes, 72% of total.
  • 28 votes, 72% of total.
  • Members 1737 posts
    June 14, 2023, 5:05 p.m.

    And inspect the image closely for artifacts.

  • Members 280 posts
    June 14, 2023, 5:06 p.m.

    I think my usual thought process is: "I wonder if there's enough depth of field? Oh well, let's hope for the best."
    When using a manual-focus lens, I can use the DoF scale on the lens.

    Don

  • Members 273 posts
    June 14, 2023, 5:10 p.m.

    Most people don't realize that re-sizing your image does indeed change DoF. I've gotten into arguments about this in the past and prepared a specific image to demonstrate that this is true.

  • Members 1737 posts
    June 14, 2023, 5:13 p.m.
  • Members 457 posts
    June 14, 2023, 5:13 p.m.

    +1
    AI = Adding Invented-details.

    Nonetheless, I was surprised at how well it sometimes worked unless more DOF was not desirable (in which case masking helps).

  • June 14, 2023, 5:16 p.m.

    More, changing viewing distance changes DOF, but we tend to associate output image size with viewing distance. I find large images which you can come right close into and still look sharp are very satisfying. They are somehow more interactive than ones with just a small enough CoC for the expected viewing distance for the frame size.

  • Members 1737 posts
    June 14, 2023, 5:20 p.m.

    When I've observed people viewing my images at exhibitions, I've noticed that they start from far away, then move in close, and then back up again. After I figured that out I started to get more picky about CoC diameter.

  • Members 457 posts
    June 14, 2023, 5:25 p.m.

    Images should be displayed on digital devices with proximity sensors: as the viewer comes closer, the image shrinks :).

  • Members 273 posts
    June 14, 2023, 8:01 p.m.

    Indeed...which is why IMAX large screens and domes are quite nice. For me (where I sit) the large screens are like 20mm-equivalent and the domes are, obviously, circular fisheye's.

  • Members 457 posts
    June 14, 2023, 8:17 p.m.

    I find that I best enjoy photographs and paintings from a certain distance. However, I am guilty of enjoying examining paintings and photographs from very close.

  • Members 435 posts
    June 14, 2023, 8:27 p.m.

    Easy for here. Macro the lenses are stopped right down and for birds and motorsports, the tele lenses are used wide open, because that's what I bought them for.

  • June 14, 2023, 8:56 p.m.

    I first experienced this when I was in my undergrad years. I went to a photo exhibition by a photographer who used a 20x16 camera with Ektachrome, displayed the slides on lightboxes on the wall. Can't remember his name. Anyhow, you could look at these things from a couple of inches (my close-up vision was pretty good in those days) and see things you couldn't see from a normal distance. I thought they were stunning.

  • Members 45 posts
    June 14, 2023, 9:08 p.m.

    That would be a first-year, basic composition/depth-of-field film test. However, since we use the same capture device for everything. Now you have to factor in changing exposure factors (aperture, shutter speed, ISO) unless testing everything on manual. You (universal you) should be testing the performance of your equipment so you know to start open, closed down, or somewhere in between for the results you want. Then, if it's critical, bracket.

  • Removed user
    June 14, 2023, 10:55 p.m.

    Or de-convolve instead.

    As to further alternatives, I rather like Merklinger's approach:

    www.trenholm.org/hmmerk/TIAOOFe.pdf

  • Members 14 posts
    June 14, 2023, 11:29 p.m.

    Back in the film days, I used the DOF scale on the lens every time. However, on "digital" lenses, the scales are so cramped that they are almost useless, so I don't use them. I just looked at a couple of my lenses and the film lens has a focus rotation of three times that of the digital lens which explains it.

  • Members 202 posts
    June 15, 2023, 3:53 a.m.

    None of the choices fit me. I would say I calculate DOF infrequently.

  • Members 545 posts
    June 15, 2023, 8:36 a.m.

    Thank you to everyone who has voted in the poll or contributed to this thread.

    What strikes me most forcefully is the distinct impression that both the understanding and use of depth of field has markedly decreased since the days of purely manual focus lenses with accurate distance scales and depth of field markings on the lens.

    I remember in the 1990s my favourite cameras were medium format rangefinders with fully manual prime lenses. It was so easy to check the depth of field from the marks on the lens. I never used the standard CoC that was used to compute those DoF marks, but instead I often used a CoC of half the standard size (and sometimes less than that). It was trivially simple to do that: if the lens was set to f/16, then I used f/8 DoF marks; and if the lens was set to f/8, I used the f/4 marks.

    It is a great pity that modern cameras so far have been unable to give us focus distance and DoF scales as accurate and easy to use as on those old manual lenses. I guess it's the price we pay for cheap and easy autofocus.

  • Members 457 posts
    June 15, 2023, 9:02 a.m.

    In my book, calculating DOF using lens marking or a hyperfocal approach should involve distance metering (e.g., laser distance meter). However, guestimating is likely the most common approach.
    Focusing at infinity is probably a better approach, even for film:
    www.trenholm.org/hmmerk/DOFR.html
    "What bothers me even more is the old story about maximizing depth-of-field by focusing at the hyperfocal distance. If you follow that advice you will be guaranteed that scenes in the distance will never be resolved any better than mediocre. You will have sealed in that "minimum acceptable standard".

    My question: is lack of precise lens markings really a bad thing?