Increasing DOF

Discussion in 'Digital Photography' started by ronviers@gmail.com, Nov 13, 2006.

  1. Guest

    What ways, other than decreasing aperture, are there to increase DOF?
    Do large format cameras or huge lenses help? What about an extremely
    sensitive sensor or a bunch of strobes?

    Thanks,
    Ron
     
    , Nov 13, 2006
    #1
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  2. <> wrote:
    > What ways, other than decreasing aperture, are there to increase DOF?
    > Do large format cameras or huge lenses help? What about an extremely
    > sensitive sensor or a bunch of strobes?


    Look up "Scheimpflug" on google. It doesn't increase DOF, but it puts the
    DOF where you want it in some cases.

    David J. Littleboy
    Tokyo, Japan
     
    David J. Littleboy, Nov 13, 2006
    #2
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  3. Shawn Hirn Guest

    In article <>,
    "" <> wrote:

    > What ways, other than decreasing aperture, are there to increase DOF?
    > Do large format cameras or huge lenses help? What about an extremely
    > sensitive sensor or a bunch of strobes?


    Sensor sensitivity has nothing to do with depth of field. More depth of
    field means a larger aperture. The physics remain the same regardless of
    the format of camera you use.
     
    Shawn Hirn, Nov 13, 2006
    #3
  4. Guest

    David J. Littleboy wrote:
    > <> wrote:
    > > What ways, other than decreasing aperture, are there to increase DOF?
    > > Do large format cameras or huge lenses help? What about an extremely
    > > sensitive sensor or a bunch of strobes?

    >
    > Look up "Scheimpflug" on google. It doesn't increase DOF, but it puts the
    > DOF where you want it in some cases.
    >
    > David J. Littleboy
    > Tokyo, Japan



    I am still processing the Scheimpflug principle but I have been
    thinking more about it and it seems like the trick lies in increasing
    the amount of parallel light striking the sensor. So a sensor with
    more surface area should increase DOF with a larger aperture. Or even
    a flash that emits coherent light. Is that correct?

    Thanks,
    Ron
     
    , Nov 13, 2006
    #4
  5. Guest

    Shawn Hirn wrote:
    > In article <>,
    > "" <> wrote:
    >
    > > What ways, other than decreasing aperture, are there to increase DOF?
    > > Do large format cameras or huge lenses help? What about an extremely
    > > sensitive sensor or a bunch of strobes?

    >
    > Sensor sensitivity has nothing to do with depth of field. More depth of
    > field means a larger aperture. The physics remain the same regardless of
    > the format of camera you use.


    I agree that the sensitivity is not a factor but I am not convinced the
    format (sensor size) is not important.

    Thanks,
    Ron
     
    , Nov 13, 2006
    #5
  6. <> wrote:
    > David J. Littleboy wrote:
    >> <> wrote:
    >> > What ways, other than decreasing aperture, are there to increase DOF?
    >> > Do large format cameras or huge lenses help? What about an extremely
    >> > sensitive sensor or a bunch of strobes?

    >>
    >> Look up "Scheimpflug" on google. It doesn't increase DOF, but it puts the
    >> DOF where you want it in some cases.


    > I am still processing the Scheimpflug principle but I have been
    > thinking more about it and it seems like the trick lies in increasing
    > the amount of parallel light striking the sensor.


    No. In a normal camera, the plane of focus is parallel to the film/sensor
    and stopping down simply increases the depth of that plane. When you
    Scheimplug, the plane of focus occurs at an angle to the film/sensor.

    At which point, if the subject _happens to lie_ in that angled plane, then
    you get the whole subject in focus despite it being at a range of distances
    from the camera. This only works for flat subjects, like sides of buildings
    or flat fields.

    David J. Littleboy
    Tokyo, Japan
     
    David J. Littleboy, Nov 13, 2006
    #6
  7. In article <>,
    "" <> wrote:

    > What ways, other than decreasing aperture, are there to increase DOF?
    > Do large format cameras or huge lenses help? What about an extremely
    > sensitive sensor or a bunch of strobes?
    >
    > Thanks,
    > Ron


    Shorter focal lengths. Shoot at 10mm and watch all the focus points
    light up at once. Unfortunately, people are going to complain that
    their portraits look like cartoon characters.

    An extremely sensitive sensor and strobes would let you close the
    aperture a lot more.
     
    Kevin McMurtrie, Nov 13, 2006
    #7
  8. Guest

    David J. Littleboy wrote:

    > No. In a normal camera, the plane of focus is parallel to the film/sensor
    > and stopping down simply increases the depth of that plane.


    But isn't the increase in depth of plane a result of eliminating
    non-parallel light?
     
    , Nov 13, 2006
    #8
  9. Paul Mitchum Guest

    <> wrote:

    > Shawn Hirn wrote:
    > > In article <>,
    > > "" <> wrote:
    > >
    > > > What ways, other than decreasing aperture, are there to increase DOF?
    > > > Do large format cameras or huge lenses help? What about an extremely
    > > > sensitive sensor or a bunch of strobes?

    > >
    > > Sensor sensitivity has nothing to do with depth of field. More depth of
    > > field means a larger aperture. The physics remain the same regardless of
    > > the format of camera you use.

    >
    > I agree that the sensitivity is not a factor but I am not convinced the
    > format (sensor size) is not important.


    The format is important only in that it contains enough information to
    pass along to the output and retain sharpness. DoF is really a measure
    of sharpness on the *print,* not the sensor.

    A huge print (wall-sized, say) from a 35mm slide isn't likely to be as
    sharp as the same sized print from a 4x5 negative. Basically, the DoF
    starts to reverse itself if it's enlarged beyond it's limit.
     
    Paul Mitchum, Nov 13, 2006
    #9
  10. Paul Mitchum Guest

    Kevin McMurtrie <> wrote:

    > In article <>,
    > "" <> wrote:
    >
    > > What ways, other than decreasing aperture, are there to increase DOF? Do
    > > large format cameras or huge lenses help? What about an extremely
    > > sensitive sensor or a bunch of strobes?

    >
    > Shorter focal lengths. Shoot at 10mm and watch all the focus points light
    > up at once. Unfortunately, people are going to complain that their
    > portraits look like cartoon characters.
    >
    > An extremely sensitive sensor and strobes would let you close the aperture
    > a lot more.


    This is why magazine ads look so sharp: All lighting is controlled.
     
    Paul Mitchum, Nov 13, 2006
    #10
  11. Guest

    Paul Mitchum wrote:

    > The format is important only in that it contains enough information to
    > pass along to the output and retain sharpness. DoF is really a measure
    > of sharpness on the *print,* not the sensor.
    >


    I see. It is because the sensor is a plane and the subject is not a
    plane. What we need are some kind of holographic sensors with billions
    of focal points.

    Thanks,
    Ron
     
    , Nov 13, 2006
    #11
  12. Bryan Olson Guest

    wrote:
    > I agree that the sensitivity is not a factor but I am not convinced the
    > format (sensor size) is not important.


    You're sort-of right, but larger formats don't increase depth
    of field. Given the same scene, vantage point, angle of view,
    f-number (lens speed), and final print size, smaller formats
    have greater depth of field.

    Note that constant f-number is not constant aperture. To get
    the same angle of view, a smaller format uses a smaller focal
    length, thus the same f-number implies a smaller aperture.


    --
    --Bryan
     
    Bryan Olson, Nov 13, 2006
    #12
  13. Bryan Olson Guest

    wrote:
    > What ways, other than decreasing aperture, are there to increase DOF?


    There's a digital tricks applicable in some cases. I doubt it answers
    your real question, but maybe you'll find this interesting:

    http://www.graficaobscura.com/depth/index.html


    > Do large format cameras or huge lenses help?


    No.

    > What about an extremely sensitive sensor or a bunch of strobes?


    With more light we get the same exposure with a smaller aperture.
    Similarly, with greater sensitivity we can capture the same image
    with less light, allowing us to stop down. So these may enable us
    to obtain greater depth of field, but they do it via the one
    method your question ruled out: decreasing aperture.


    --
    --Bryan
     
    Bryan Olson, Nov 13, 2006
    #13
  14. Paul Mitchum Guest

    <> wrote:

    > Paul Mitchum wrote:
    >
    > > The format is important only in that it contains enough information to
    > > pass along to the output and retain sharpness. DoF is really a measure
    > > of sharpness on the *print,* not the sensor.
    > >

    >
    > I see. It is because the sensor is a plane and the subject is not a
    > plane. [..]


    Nope.
     
    Paul Mitchum, Nov 13, 2006
    #14
  15. Bryan Olson Guest

    wrote:
    > Bryan Olson wrote:
    >
    >> You're sort-of right,

    >
    > My life story.


    Yeah, join the club

    > I cannot see an iris in my cell phone to control aperture - it may not
    > even have one. I guess it is because the lens is so small and close to
    > the sensor that it does not need it. Do you have a guess as to what
    > the focal lenght of a Nokia cell phone is?


    Why guess when we can Google? Trying 'Nokia camera "focal length"',
    and glancing at the top hits, I see 3.5mm, 4.5mm, 5.5mm, and a few
    others around the same range.

    I'm a bit surprised at the question. I often notice atrocious
    defects in photos from cell phones, but insufficient depth of field
    is not one of them.


    --
    --Bryan
     
    Bryan Olson, Nov 13, 2006
    #15
  16. Guest

    Bryan Olson wrote:
    > wrote:
    > > Bryan Olson wrote:
    > >
    > >> You're sort-of right,

    > >
    > > My life story.

    >
    > Yeah, join the club
    >
    > > I cannot see an iris in my cell phone to control aperture - it may not
    > > even have one. I guess it is because the lens is so small and close to
    > > the sensor that it does not need it. Do you have a guess as to what
    > > the focal lenght of a Nokia cell phone is?

    >
    > Why guess when we can Google? Trying 'Nokia camera "focal length"',
    > and glancing at the top hits, I see 3.5mm, 4.5mm, 5.5mm, and a few
    > others around the same range.
    >
    > I'm a bit surprised at the question. I often notice atrocious
    > defects in photos from cell phones, but insufficient depth of field
    > is not one of them.
    >
    >
    > --
    > --Bryan


    I am surprised by my complete lack of curiosity about my cell phone
    "camera". There was a day when I would have at least been
    interested enough to disassemble it and put the parts under the
    microscope. Honestly, tonight was the first time I looked at it and
    the first picture I took was of the objective of the stereo zoom I was
    using to look for an iris - it was atrocious.

    Ron
     
    , Nov 13, 2006
    #16
  17. wrote:
    > What ways, other than decreasing aperture, are there to increase DOF?
    > Do large format cameras or huge lenses help? What about an extremely
    > sensitive sensor or a bunch of strobes?
    >
    > Thanks,
    > Ron


    You might be interested to see
    http://www.syncroscopy.com/syncroscopy/automontageshort.asp
    for a software solution to this problem, mainly used in microscopy
    where DOF at high mag is often smaller than the objects you're looking
    at.
     
    Al, Cambridge, UK, Nov 13, 2006
    #17
  18. acl Guest

    wrote:
    > Paul Mitchum wrote:
    >
    >>The format is important only in that it contains enough information to
    >>pass along to the output and retain sharpness. DoF is really a measure
    >>of sharpness on the *print,* not the sensor.
    >>

    >
    > I see. It is because the sensor is a plane and the subject is not a
    > plane.


    No. Go here:
    http://en.wikipedia.org/wiki/Depth_of_field#Basis_of_the_DOF_formulae
    and scroll down to part 11 ("Basis of DOF formulae").

    The effect of changing the sensor size is to force us to change the
    circle of confusion required to obtain an equivalent definition of
    "sharp" for the same print size. This is because we are talking about
    the range of distances from the camera that appear sharp on a print of a
    given size (as opposed to on the negative).

    As an amusing aside, if you keep the distance, lens and f-stop the same,
    and use a larger sensor, you will get more DOF in the final print.
     
    acl, Nov 13, 2006
    #18
  19. Jim Townsend Guest

    wrote:

    > What ways, other than decreasing aperture, are there to increase DOF?
    > Do large format cameras or huge lenses help? What about an extremely
    > sensitive sensor or a bunch of strobes?


    High ISO and bright light will allow the smaller aperture
    required for a wide DOF.

    DOF is also dependent on focal length. It's easier to
    get good DOF with wide angle lenses than it is with
    telephoto.

    If you're changing cameras for a different format size, you
    want a smaller sensor. They use comparatively smaller lenses
    which are shorter in focal length and have smaller apertures.
     
    Jim Townsend, Nov 13, 2006
    #19
  20. Jim Townsend Guest

    Shawn Hirn wrote:

    > In article <>,
    > "" <> wrote:
    >
    >> What ways, other than decreasing aperture, are there to increase DOF?
    >> Do large format cameras or huge lenses help? What about an extremely
    >> sensitive sensor or a bunch of strobes?

    >
    > Sensor sensitivity has nothing to do with depth of field. More depth of
    > field means a larger aperture. The physics remain the same regardless of
    > the format of camera you use.


    The sensor sensitivity doesn't *directly* affect DOF, but it does allow
    you to stop the lens down more and still get a proper exposure.
     
    Jim Townsend, Nov 13, 2006
    #20
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