Student Photographer needs technical advice

Discussion in 'Digital SLR' started by Gina in Florida, Nov 18, 2004.

  1. Hey there -- This is my first post. I am a student photographer at
    University of South Florida -- St Petersburg.

    Later today I'll get the chance to make photos of juveniles at an area
    correctional facility. They are puppy-raisers for a guide dog school
    in this area.. If you've seen Animal Planet's "Cell Dogs" you
    understand what I'm talking about.

    I am assigned to make a photo essay -- and -- one portrait. Since
    these are juveniles -- I can't photograph their faces.. I can,
    however, photo the guide dog representative, and maybe a guard -- if
    they give permission.

    I thought I'd try a silhouette shot for the portrait. I could use some
    technical advice about shooting silhouettes.

    I have a brand new Canon Digital Rebel. I own a 50 mm lens, a 70-300mm
    lens; and a 24mm wide angle lens. I do not own any other equipment.
    (That was expensive enough for now!)

    I am also having issues reaching deep depth of field in bright
    sunlight -- so far I can only achieve it using my telephoto lens.

    If any of you have time to offer advice -- I'd really appreciate it. I
    still can't believe that I've been given permission to be in a PRISON.
    I leave to shoot the assignment in 2.5 hours.. I'll stay on this site
    reading responses till them..
    _________________
     
    Gina in Florida, Nov 18, 2004
    #1
    1. Advertisements

  2. Gina in Florida

    YAG-ART Guest

    First you should be asking your instructor, thats what they get paid
    for. As for reacing depth of field, sounds like you don't know what
    depth of field is. Depth of field has nothing to do with the lens,
    and all to do with apature. The smaller the apature the larger the
    depth of field. So what is depth of field? It is the distance in
    front of and behind the point of critical focus, that is in acceptable
    foucs (it looks like its in focus to the human eye).
     
    YAG-ART, Nov 18, 2004
    #2
    1. Advertisements

  3. Gina in Florida

    Voice Only Guest

    Interesting.
    Hmm, if you can, get a great backthat is really brightly light, or
    over light it. Then set the camera to meter off the extremely bright
    background. Have the "kids" stand in front, or kneeling down.. no flash.
    They should silhouette pretty good I would think.
    All on a tripod.
    Don't move anything.
    Shoot the dogs, with flash, near the 'kids' positions, and layer the
    2 images, to get good pics of dogs, with sil's of the 'kids'
     
    Voice Only, Nov 19, 2004
    #3
  4. Gina in Florida

    Steven Wandy Guest

    sounds like you don't know what
    Actually it sounds like the student knows more than you do.
    You don't realize that the FOCAL length of the lens also determines
    the amount of depth of field? Such as a WIDE angle lens has much
    more DOF than a TELEPHOTO one. Isn't that why most portrait
    photographers use moderate TELEPHOTO lens because it
    gives them better DEPTH OF FIELD???
     
    Steven Wandy, Nov 19, 2004
    #4
  5. No, portrait photographers use moderate telephoto lenses to minimize
    distortion (caused mainly by being too close) and to allow them to fill the
    frame while keeping the subject more comfortable. Also the less depth of
    field of the telephoto lens (compared to a "normal") helps to control the
    background.

    And for what it's worth, he's right in saying that depth of field has
    nothing to do with the lens (mostly right anyway). Depth of field is
    controlled by the actual opening of the lens and the relative size of the
    image on the negative to the subject (assuming the same print sizes). If you
    take a wide angle lens and fill the frame with your subject then fill the
    frame with the same subject using a telephoto lens and print both pictures
    to the same sizee you'll have the same depth of field in both shots. If you
    fill the frame with your subject using a telephoto lens then switch to a
    wide angle lens but DON'T move the camera or the subject then you'll see a
    much greater depth of field with the wide angle lens because the image of
    the subject will be much smaller on the negative the the image shot with the
    telephoto lens.

    Jeffery S. Harrison
     
    Jeffery Harrison, Nov 19, 2004
    #5
  6. Gina in Florida

    YAG-ART Guest


    The focal length has no effect, its all distance from subject.
    Portrait photographers use a medium telephoto so they don't get
    distortion and have a good working distance from the subject.
     
    YAG-ART, Nov 19, 2004
    #6
  7. Gina in Florida

    Steven Wandy Guest

    I realize that they use short telephoto lens to fill the frame without
    getting into the face of the model (which would cause distortion if using a
    wide angle lens), but you can't tell me that any particular aperture on a
    wide angle lens would give the same depth of field as that same aperture on
    a telephoto lens? I realize that aperture and lens to subject distance have
    larger effects on DOF, but the focal length of the lens being used also
    effects it.
     
    Steven Wandy, Nov 19, 2004
    #7
  8. Gina in Florida

    Steven Wandy Guest

    I realize that they use short telephoto lens to fill the frame without
    getting into the face of the model (which would cause distortion if using a
    wide angle lens), but you can't tell me that any particular aperture on a
    wide angle lens would give the same depth of field as that same aperture on
    a telephoto lens? I realize that aperture and lens to subject distance have
    larger effects on DOF, but the focal length of the lens being used also
    effects it.
     
    Steven Wandy, Nov 19, 2004
    #8
  9. Gina in Florida

    JPS Guest

    In message <jsfnd.8061$>,
    There are a number of ways to look at it, but one very simple and
    important thing to remember is that (all other things being equal), two
    images with the same subject size in the frame and the same f-stop will
    have the same DOF.

    You don't get greater DOF by moving closer to your subject and using a
    shorter focal length lens!

    The same subject taken at the same f-stop with a 100mm lens instead of a
    400mm lens, from 1/4 the distance, will have the same DOF.

    You choose the focal length by how close you want to be to the subject,
    what kind of perspective you want, and how much camera shake the FL can
    handle.


    --
     
    JPS, Nov 19, 2004
    #9
  10. Gina in Florida

    JPS Guest

    In message <PBrnd.18278$>,
    .... not with the same f-stop and subject size on the recording medium.
    --
     
    JPS, Nov 19, 2004
    #10
  11. Gina in Florida

    John Francis Guest

    But the focal length of the lens also affects the lens-to-subject distance,
    assuming you maintain the same ratio of subject image to overall frame size.
     
    John Francis, Nov 20, 2004
    #11
  12. Gina in Florida

    Hunt Guest

    This is probably too late to help you assignment - and I hope it turned out
    well for you.

    As for your silhouette portrait, find a bright, sunlit background, and set
    your exposure for it. Add about 1-2 /f exposure, to get it near white, and
    place your subject in the shade, or away from the sunlight hitting that
    background. Use a longer lens, or longer range within your zoom. Shoot with a
    wider aperture, i.e. lower #. Don't let the camera's meter choose your
    subject, but hold/set the auto exposure (or use manual exposure, if you can),
    on the background + exposure compensation to get it brighter than 18% grey.

    Again, good luck,
    Hunt
     
    Hunt, Dec 4, 2004
    #12
    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.