Shallow Depth of field help

Discussion in 'Beyond the Basics' started by Kryg, Oct 27, 2008.

  1. Kryg

    Kryg TPF Noob!

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    I think I posted this on the wrong thread before so I'm reposting it here I think this is where it belongs

    Hello I’m having trouble shooting a photo with a shallow depth of field and cannot figure out what I’m doing wrong. I'm getting too much background the link is to one of my photos for an example. I'm using a Nikon D80 with a Tamron AF 18mm to 200mm lens 1:3.5-6.3. I have tried shooting with AF on and I’ve tried manual focus, F5.6, 1/200 and ISO of 200.


    http://farm4.static.flickr.com/3162/2979097390_ab47c5eafb_b.jpg
     
  2. tsaraleksi

    tsaraleksi TPF Noob!

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    What focal length were you at? How far away were you from the subject? At f/5.6 you're going to be getting a fair amount of depth unless you are pretty close up on the subject, at maximum zoom.
     
  3. Kryg

    Kryg TPF Noob!

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    75mm and about 15 feet away.
     
  4. tsaraleksi

    tsaraleksi TPF Noob!

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    There is nothing you can do with that lens and combination of factors to reduce your depth of field. You need to either use a much longer focal length and get further away, or use a lens with a much larger available f/stop.
     
  5. Mike_E

    Mike_E No longer a newbie, moving up!

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    OK, it;'ll cost you about $120 delivered (Nikon 50mm f/1.8). Click the B&H or Adorama link at the top of the page.

    If you want extreme DoF then either save up for an f/1.2 or get an extension tube (the tube will give you an outrageously narrow DoF).
     
  6. andrew99

    andrew99 TPF Noob!

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    You mean you are trying to blur the background to separate the subject from the background? Ideally you would use a lens with a larger aperture (like a zoom with a constant f2.8 or a prime with f1.8 or f1.4). But without changing your lens, try using a large aperture as possible (small f number), and bring the subject closer to the camera.
     
  7. Village Idiot

    Village Idiot No longer a newbie, moving up!

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    Online DOF calculator
    http://www.dofmaster.com/dofjs.html

    At a given focal length, the farther you are from a subject, the more DOF you will have. 70mm at 15' = about 2.75' DOF. 70mm at 1' distance (provided if that was possible) = .01' DOF.

    Now if you were to step back to about 40' and shoot at 300mm with f/5.6, you'd have 1.2" DOF because as you increase focal length, DOF changes. Try this and see if there is something you can do with that lens to get the desired result.

    DOF does not depend strictly on aperture. Play with the calculator a bit and you'll see.

    The below photo was shot at f/9 and has much less DOF. If the calculator is spot on shooting at 41mm, f/9 and 2' distance between the camera and me, then DOF is only .23. So about 1.2" of DOF, even at f/9.

    [​IMG]
     
  8. Kryg

    Kryg TPF Noob!

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    Well I tried a shot at 32mm with f4.2 at about 6 inches a got the effect but that is to insanely close so I guess I’m going to have to buy a new lens. o well
     
  9. Dao

    Dao No longer a newbie, moving up!

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    In other words, if the subject is closer to your camera, or if the background is farther away from the subject. You can still create the blur background type of photos. You just need to play around with it and see.

    And yes, check with the DoF calculator, it will give you a good idea how to create a blur background type photos.
     
  10. JerryPH

    JerryPH No longer a newbie, moving up!

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    You can't break the laws of physics... it's a combination of aperture vs distance between you and the subject vs the distance from camera behind the subject.

    You can get well blurred pictures with a small aperture, you just have to understand how it works:

    [​IMG]

    This picture was taken at F/7... yet both the foreground and background have good amounts of bokeh. What made this possible is that I was at 200mm. HERE is the supporting EXIF info from Flickr.
     
  11. beaminge36

    beaminge36 TPF Noob!

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    Separate your subject. In the example photo your shooting at the ground. If you put your pumpkin (im assuming that was your point of interest) on top of something and left 30 feet of space behind it and the background, the background would be far more blurred. You can achieve decent bokeh with a slower lens but you are limited to the scenarios that will produce that subject isolating blur.

    Nick
     
  12. mrodgers

    mrodgers No longer a newbie, moving up!

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    Hmm, pumpkin haphazardly laying in the yard along with the planter. Paper garbage laying about. Leaves scattered. Swingset and kid's toys laying around......

    Get yourself a longer lens. I don't want you in my yard taking pictures of my stuff. Go out on the public road with a longer lens if you want pictures of my yard!

    :mrgreen::lol::mrgreen:
     

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