Depth of Field Quest. From Newbie, Please

Discussion in 'Digital Photography' started by Robert11, Aug 29, 2004.

  1. Robert11

    Robert11 Guest

    Hello:

    Newbie Photographer.

    Have a question about depth of field.
    Have been experimenting a bit, but haven't been able to reach any firm
    conclusion on this.

    Let's say I have a subject in the foreground, perhaps six feet or so away,
    and also some
    real pretty mountains at infinity that I would also like to be in focus, and
    clear.

    I would like the close in subject and also the mountains to both be in
    focus.

    For a sunny day, am I better off focusing on the subject, or setting my
    distance to infinity ?
    Why ?

    Does the answer change if it is cloudy out, and i guess my aperture would be
    much larger ?

    Thanks,
    Bob
     
    Robert11, Aug 29, 2004
    #1
    1. Advertisements

  2. There is a setting called hyperfocal distance that you shall
    use if you want both the background and the foreground to
    be sharp. This setting is a compromise between infinity
    and the nearest sharp object.

    You can find a calculator for the hyper focal distance here
    http://www.tangentsoft.net/fcalc/

    You have to remember to use the actual focal length and the
    actual sensor size.

    And - yes - the focal depth is much larger in bright weather,
    i.e. when you step the camera down.


    /Roland
     
    Roland Karlsson, Aug 29, 2004
    #2
    1. Advertisements

  3. Roland Karlsson, Aug 29, 2004
    #3
  4. Robert11

    Tony Spadaro Guest

    Tony Spadaro, Aug 29, 2004
    #4
  5. Robert11

    jpc Guest


    Amusing.

    But a little misleading in a digital group. With the toughly 5X
    greater DOF that most of have over 35 mm film, manually focusing in
    the aperture priority mode becomes a very useful technique. Got
    shutter lag problems when the grandkids are dashing about in the back
    yard. Disable autofocus and you'd be surprised how fast your camera
    responds.

    jpc
     
    jpc, Aug 30, 2004
    #5
  6. Robert11

    Mark Mestman Guest

    Newbie,

    Keep it simple.....

    Depth of field depends only upon the size of the camera's aperature,
    sunny day, cloudy day, indoors or underwater, no matter.

    The smaller the aperature, the greater the depth of field. The larger
    the aperature, the less depth of field. F22 is a small aperature, F4
    is a large aperature.

    This is because light is infinately in focus thru a pinhole. Make
    your aperature like a pinhole in order to gain maximum depth of field.

    Demonstrate the above principle to yourself.... poke a pinhole thru a
    blackened piece of cardboard or piece of black paper and peek thru the
    hole.....the mountains in the background, the car across the street
    and the person standing right in front of you will all be in focus.

    To capture the shot you describe with all in focus, set your aperature
    as small (f22 or smaller) as good exposure will permit....you will
    have to use a slow shutter speed to maintain good exposure with such a
    small aperature.

    Shoot for the smallest aperature you can, and you will be happy with
    the depth of field.

    Hope this helps!

    Mark
     
    Mark Mestman, Aug 30, 2004
    #6
  7. Robert11

    Tony Spadaro Guest

    Tony Spadaro, Aug 30, 2004
    #7
  8. Robert11

    Nostrobino Guest

    Somewhere in between. If your camera doesn't allow manual focus this may be
    difficult to do, but you may be able to find some object farther away than
    your main subject that you can lock focus on and then recompose the shot as
    you like. This will probably take some experimentation in order to give you
    the best results.

    What you are concerned with here is called "depth of field"--the range of
    distances in front of the camera in which the subject appears to be sharply
    focused. Depth of field (DoF) varies with focal length (the longer, the
    shallower the DoF), aperture (the larger, the shallower the DoF), subject
    distance (the closer, the shallower the DoF) and final image magnification
    (the greater, the shallower the DoF).

    The greatest range of sharpness for all subjects INCLUDING those at infinity
    occurs when the camera is focused on the "hyperfocal distance"--the distance
    at which everything from half that distance to infinity will appear to be
    sharp. But this may be difficult for you to do in any case, and especially
    with a digital camera.

    That may or may not be true. Some digital cameras tend to keep the lens wide
    open most of the time, regardless of whether it's sunny or cloudy. If your
    camera "stops down" the lens in sunnier conditions, or allows you to choose
    a smaller aperture, then yes, that will give you more DoF which is of course
    what you want. Be aware that a smaller aperture will force the camera
    (assuming full auto exposure) to go to a slower shutter speed and/or a
    higher ISO speed, and either of these may (but will not necessarily) have an
    unfavorable effect on the photo.

    For what you want to do, make sure you're using the shortest focal length
    (widest angle), assuming your camera has a zoom lens. If your subject is as
    you say six feet or so away, try locking focus on some other object 10 or 12
    feet away, then recompose and take the shot. If this leaves your subject
    unsharp, either stop down to a smaller aperture (if your camera permits
    this) or try locking focus on a closer distance. If that still doesn't give
    you the results you want, you may have to back farther away from the
    subject, or just settle for having the subject sharp and the background as
    little unsharp as possible.

    N.
     
    Nostrobino, Aug 30, 2004
    #8
  9. Robert11

    Nostrobino Guest

    Well, that was pretty nasty.

    Nothing in jpc's comment justifies that sort of hostility or insult, and
    nothing in the OP's post suggested or implied that his camera had any "DOF
    preview in the first place." The vast majority of digital cameras do not,
    and since the OP is a self-described newbie it seems unlikely that he has a
    digital camera with DoF preview.

    N.
     
    Nostrobino, Aug 30, 2004
    #9
  10. Robert11

    jpc Guest

    Ah--the famous kill file strategy. Never could see much point to that.
    Since I'm in your killfile, you are never going to have a chance to
    respond to all the nasty things I might decide say about you over the
    next three years.

    And of course you also cut out what I said. Snip, snip, snip and than
    insult. Very .... infantile might be the right word.

    Anyway, I'll quote both of us and let the rest of the group decide
    who's the jerk and ass

    Me---- Amusing.

    Believe it that was intended as a compliment, something I doubt I'll
    repeat.

    You---If you only use a P&S you have no DOF preview in the first
    place, jerk.


    What ever gave you that idea? Read the rest of my message and you will
    see I was talking about aperture priority which mean I have the full
    boat of controls, shutter, aperture, manual exposure and focus, macro
    etc. Hardly a lowly P&S. Unless, of course, your definition of a lowly
    P&S is any camera you don't own. There's been some of that going
    around recently

    And in case you haven't noticed, digital camera don't have a DOF
    preview button. That a 35 mm film thing.Me But a little misleading in a digital group.

    Some facts

    With my camera and its 5X crop factor, if I manually focus at 9 ft,
    set the zoom to the equivalent of a 50 mm lens and set the aperture at
    f5.6 I have a DOF of 4.5ft to 900ft. Very useful.

    With a 35 mm camera the DOF of field is ony 7ft to 12 ft. Not all that
    useful.

    So confusing the OP with 35 mm info when he was asking about digital
    cameras wasn't a little misleading. It was completely misleading.


    You---If you can't say something intelligent -


    To expand on my original post.

    When I set up my camera this way and lock the exposure, either by
    setting the shutter speed or by using the spot meter and exposure lock
    button I have virtually no shutter lag. Moreover if I go into the
    multiple image mode I can snap off up to 17 pic in about 8 sec before
    the camera's buffer fills and it has to take a few seconds to write to
    the memory card.

    Is this the answer to all the problems in digital photography? Of
    course not. But it is a reasonablely intelligent workaround for when
    you have a fast moving subject that may do some unexpected and
    photographically interesting things while he she or it is still
    visible in the viewfinder,

    jpc
     
    jpc, Aug 30, 2004
    #10
  11. Robert11

    jpc Guest

    Thanks for jumping to my defense. You did it so nicely I almost wish
    I'd been a trifle nicer when I defended myself--althought I must
    confess the operative word is 'almost.'

    Anyway, after thinking about it and doing a few experiments, it looks
    like most of us have a DOF preview button and screen--the shutter
    button and LCD on the back of the camera.

    I put my camera in manual and macro mode, half pressed the shutter to
    spot focused on a cactus six inches in front of me, and raised the
    camera to see what was in focus. At f2.8 there wasn't much in focus
    besides the cactus, at f11 the whole kitchen was closed to being in
    focus.

    A simple and graphic demostration of DOF--one I'll have to remember
    the next time I'm trying to explain the concept.

    Oh, what the hell--Thanks Tony for making me think a bit more about
    DOF.

    jpc
     
    jpc, Aug 30, 2004
    #11
  12. Robert11

    Tony Spadaro Guest

    If you can't figure out how to find the dof using the screen on the back of
    the camera than you are as brain dead as the other troll - aren't you.
    Actually you are probably the same troll. I don't care if you actually are
    someone different - you obviously have the same lack of brain.

    --
    http://www.chapelhillnoir.com
    home of The Camera-ist's Manifesto
    The Improved Links Pages are at
    http://www.chapelhillnoir.com/links/mlinks00.html
    A sample chapter from my novel "Haight-Ashbury" is at
    http://www.chapelhillnoir.com/writ/hait/hatitl.html
     
    Tony Spadaro, Aug 30, 2004
    #12
  13. Robert11

    Alan Browne Guest


    Tony's mission is not to reveal the secrets of DOF as much as to
    draw traffic to his websites and his amusing attempt at getting
    his book recognized and published. (Note his tenacious
    top-posting and somewhat tedious sig lines).

    Once upon a time somebody asked about a DOF calculator. Tony
    replied with a link to his own pages, saying there would be a
    link to fcalc therin... I replied to Tony's post and to the OP
    with the fcalc link directly (and chided Tony at the same time)
    and this has pissed Tony off so much that I am (he claims) a
    permanent resident of his killfile...

    Tony has squandered a lot of previously earned goodwill over the
    past year. I hope that his recently corrected cataracts will
    allow him to photograph more, be an asshole less and deal with
    adversity with more mature actions than declaring people members
    of his killfile... although, therein it is nice and cuddly.

    Cheers,
    Alan
     
    Alan Browne, Aug 30, 2004
    #13
  14. Robert11

    Alan Browne Guest

    Oh, but he will... he'll reply to others replies where you appear
    and attack you there. Have fun!
    No need. It's clear. And Tony can only killfile a person once
    which is probably REALLY frustrating to him, eh Tony?
     
    Alan Browne, Aug 30, 2004
    #14
  15. Robert11

    Nostrobino Guest

    That doesn't work on many digital cameras. You need to get out more.

    Not worth any extra effort, so I'll just paste in here the last part of my
    reply to jpc:
    The bottom line here is, obviously, that Tony's lavish admiration of his own
    expertise is centered on what he understands of his own limited experience.

    N.
     
    Nostrobino, Aug 31, 2004
    #15
  16. Robert11

    Nostrobino Guest

    You're welcome.

    Well, that depends. . . . Do you have a digital SLR? I don't.

    Sure, but the question is whether that is something usable by the OP. He
    describes himself as a newbie but doesn't mention the kind of camera he's
    using. I am assuming it is probably a relatively simple camera,
    auto-everything but not allowing much in the way of manual control.

    For example, my Minolta Xt and Xg cameras don't have any means of manually
    controlling the aperture. And these are extremely popular models.

    My other digital cameras all do, but repeating the experiment you describe
    doesn't show any difference in DoF on the LCD monitor at all on my 7i. I can
    get to about six inches (from the front of the lens) to the calendar in
    macro mode, which this camera allows only at 28mm and 200mm (equiv.)
    settings. At 28mm I have f/2.8 wide open and f/8 stopped all the way down.
    Half pressing the shutter to lock focus and then pointing at the other end
    of the kitchen looks EXACTLY the same to me on the LCD monitor at either
    aperture setting. At 200mm I have f/3.5 wide open and f/9.5 stopped down.
    Doing the same thing produces the same result, no apparent difference at all
    on the monitor. So evidently on this camera going into aperture priority and
    changing the setting doesn't actually change the aperture until the moment
    of exposure.

    Even if there were a visible difference, I doubt very much it would be of
    much use for gauging DoF because of the coarseness of the LCD screen. I
    don't even think DoF preview buttons on 35mm SLRs are as useful for that as
    other people seem to think. That is, what you see in the viewfinder stopped
    down gives you some sense of DoF change as the aperture is changed all
    right, but it doesn't really show you in any CRITICAL way what the range of
    apparent sharpness will be on, say, an 8x10 or larger print. I think the DoF
    preview is useful for getting some general sense of what relative sharpness
    in different parts of the photo will be like, but nothing more than that.

    I've just tried the same thing with my S414, same result. Locking focus on a
    close object in macro mode (78mm equiv. f.l.) and then pointing at a distant
    subject, looks exactly the same on the LCD at f/3.6 as it does at f/8 (the
    only two apertures available in this mode). Also, going into manual focus on
    S414, macro mode, setting at the closest focus, switching back and forth
    between wide open and stopped down shows no difference at all with a distant
    object on the monitor with the shutter release half pressed. Taking the shot
    in each case does show an obvious difference in DoF, of course.

    The bottom line here is, obviously, that Tony's lavish admiration of his own
    expertise is centered on what he understands of his own limited experience.

    N.
     
    Nostrobino, Aug 31, 2004
    #16
  17. Robert11

    Nostrobino Guest

    ----- Original Message -----
    From: "Alan Browne" <>
    Newsgroups: rec.photo.digital
    Sent: Monday, August 30, 2004 6:13 PM
    Subject: Re: Depth of Field Quest. From Newbie, Please

    Ah. Until you mentioned it I hadn't noticed--I rarely bother reading those
    lengthy kinds of sigs.

    I have to wonder about people who claim to do that so much. I can understand
    plonking (and have plonked) a very few people whose posts seemed only
    intended to be aggravating or insulting and with no redeeming value. I just
    have no further interest in anything they have to say.

    You, on the other hand, I cannot imagine ever killfiling under any
    circumstances. We have argued strenuously and even with mutual exasperation
    over some issues as I recall, but such disputes have always been
    thought-provoking, good gray-cell exercise and worthwhile.

    Well, since he hasn't claimed to have killfiled me yet I suppose he will
    read your comments here.

    N.
     
    Nostrobino, Aug 31, 2004
    #17
  18. Robert11

    jpc Guest

    No I have a 3 year old Olympus 3020Z, Not the latest and greatest but
    it does have all the controls.
    On mine, the differences are strinking. Obviously-- and not
    surprisingly--different manufactures do things in different ways.
    Agreed. If you want to find out what is truly going on you have to set
    up a test scene (the classic signs-every-few-feet, for instance) and
    take pictures. But this is more important for film and large sensors.
    One of the biggest advantages with small sensors is that they are so
    forgiving to focus errors. The flip side is that it become almost
    impossible to completely blur a background.

    If the original poster hasn't been driven off by either the confusing
    advice or the mini flame war, come back and tell us what camera you
    have.

    jpc
     
    jpc, Aug 31, 2004
    #18
  19. Robert11

    Archibald Guest

    Not so -- he has kill-filed me many times. He even replied to one of
    them where I said, "No you haven't!". What a moron!

    Most folks that are bothered by a thread or author will quietly filter
    those posts out... but not our little Tony. He has to make a fussy
    show about it, as though to intimidate those of us who have not yet
    received his ultimate punishment.

    And what punishment it is to be kill-filed by this little tyrant...
    not. He doesn't seem to understand that kill-filing affects only him.

    A.
     
    Archibald, Aug 31, 2004
    #19
  20. Robert11

    Alan Browne Guest

    Blush. Not sure they go that far, but it is better to argue
    sanely than to ignore completely. In most NG arguments both
    positions are often saying the same thing in a different way, but
    neither understands the others frame of reference until long
    after the insults begin. I have used filters from time to time
    when warranted, but that's not aimed at people in the NG.

    Cheers,
    Alan
     
    Alan Browne, Aug 31, 2004
    #20
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.