Blurred Background

Discussion in 'Photography Beginners' Forum' started by RobinChen, May 17, 2007.

  1. RobinChen

    RobinChen TPF Noob!

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    Ok I am a big fan of the whole blurred background effect. I know that this is created by a larger aperture size, causing a smaller DOF. I however use a 28-135mm 3.5-5.6 len and I'm not able to get as much blurred background as I want. How would I do some digital editing in PS to obtain such results. And two what is a good lens that you guys recommend for this type of photo.

    Thanks in advance,
    Robin
     
  2. DSLR noob

    DSLR noob TPF Noob!

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    Cheap fix to your problem. Canon EF 50 1: 1.8 MK II $75 USD. No more questions needed.
     
  3. Sw1tchFX

    Sw1tchFX TPF Noob!

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    I have never seen anyone successfully make a background out of focus digitally before. The whole process of doing it is just bad and not a good idea to boot. When you take portraits, take them at 135mm, open up your aperture, and get close.
     
  4. Alex_B

    Alex_B No longer a newbie, moving up!

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    true, going to the long end of the lens helps.

    and digital background blur just looks strange, not like a nice bokeh.
     
  5. RobinChen

    RobinChen TPF Noob!

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    Awesome! Just if you dont mind, could you explain why at 135 f/5.6 the portrait would be more blurred in the back as compared to 28 f/3.5? Not exactly sure how does the end of the zoom lens help compared to the smaller aperture.

    In the meantime, time to go try it out!
     
  6. firemedic0135

    firemedic0135 TPF Noob!

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    the depth of field(dof) is decreased with the larger aperture,the longer the focal length,the closer the subject is to the lens. combine all three and you have a thin dof.
     
  7. Garbz

    Garbz No longer a newbie, moving up!

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    Well at 28mm the lens has a wider open aperture granted, but as kind of mentioned in the above post a longer focal length also contributes. Perhaps someone else can tell you the maths behind it, but if you look at pictures taken with a fish-eye lens everything (nearly) is in focus. Short focal lengths have greater depth of field and the affect is greater for the focal length in this case then aperture.

    If you had say a 17-55mm f/2.8 lens. Even though it's f/2.8 over the entire range, at 55mm the background would be more blurred than at 17mm.
     
  8. Sw1tchFX

    Sw1tchFX TPF Noob!

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    ^^ way to go team! :thumbsup:
     
  9. RobinChen

    RobinChen TPF Noob!

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    :thumbup: YOU GUYS ARE AWESOME!. I did take a picture zoomed in on a bottle, and another one just standing next to it without zoom. the background seems more blurred with the one zoomed in. Someday I'll understand the math behind it. For now, I'll just go take more pictures!
     
  10. EOS_JD

    EOS_JD TPF Noob!

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    28mm f3.5 with 10' to subject has a dof of about 5.4'

    135mm f5.6 with 10' to subject has a dof of 0.34'

    So using this you can generally calculate the dof for any given aperture/lens/distance combination.

    http://www.dofmaster.com/dofjs.html

    Cheers
    jim
     

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