DOF (wonder how many posts have been made about this topic) ;)

Discussion in 'Photography Beginners' Forum' started by sunbeam, Jul 9, 2009.

  1. sunbeam

    sunbeam TPF Noob!

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    I am sure this question has been asked a million and one times before, but hopefully those of you who aren't ameteurs like me, don't mind answering it for a million and second time ;)

    I have a 50mm 1.4 pentax lens, and was taking some portraits of my dad, and once I got them up on my comp noticed ALOT of blurring of his face. I had the aperature open all the way on most shots, and had a quick shutter speed and also I've had trouble with my diopter being off before, so I'm not sure what the prob is.

    So my question is, when you have your ap. set at say between 1.4 and 2.8..... what is the maximum distance you should be away from you subject??? Thanks to all who respond.
     
  2. meme84

    meme84 TPF Noob!

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    I am of no help but this is a great question I will be intersted in the replys
     
  3. PhotoXopher

    PhotoXopher TPF Noob!

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  4. Dao

    Dao No longer a newbie, moving up!

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    First, you may need to read up about DoF. Once you understand what it is and what factors will affect the Dof, you maybe able to answer the question yourself.

    In the mean time, take a look at this online DoF calculator

    Online Depth of Field Calculator


    Play around with it and the main thing is try to get a combination that the "Total Depth of Field" is deep enough to have the subject in focus (i.e. 1 or 2 feet)
     
  5. kundalini

    kundalini Been spending a lot of time on here!

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    I'd much rather try to be helpful for (another) question about DoF, ISO, or whatever rather than "which lens, which camera, which brand..."

    You have just proven a point that many should learn from. Just because you can open up your apeture to f/1.4 doesn't mean it's the best setting. For portrature I think you'll find that stopping down the lens to at least f/4, you will get much more pleasing results to having the face and most of the head in focus while still creating some nice bokeh. This is also dependant of the camera-to-subject and subject-to-background distances.
     
  6. Samanax

    Samanax TPF Noob!

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    Depth Of Field (DOF) is affected by 4 things...aperture size, distance between the camera and the subject, focal length of the lens and distance between the subject and the background.

    The closer you get to your subject the shallower the DOF gets. So if you want to be sure that the entire subject stays in focus you have to use a smaller aperture (high f/stop setting) to increase the DOF.

    Examples for Understanding Depth of Field
     
  7. benhasajeep

    benhasajeep TPF Noob!

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    To, add what was said above. The closer you are to a subject to smaller the dof will be for a given setting. IE at 1' the dof may be 2" deep. At 100' it may be 10' deep. Lenses used to have this nice scale that you could use. Apparently photographers don't need them any more. :er:

    Using a lens wide open in a portrait situation is not enough dof range. Also you mention diopter? You really don't have to have that fast of a shutter with a 50mm. Stop the lens down several stops and give it another try. Also most lens sweet spots are a couple stops down from max. Are you using a diopter on top of the lens as well? The 50mm lens should be ok as a portrait lens on its own. Maybe a little on the short end (will give a slight widening effect to the subject). But adding a diopter may make the situation worse. As most are not designed to work with a specific lens. So they add some faults to the mix.
     
  8. KmH

    KmH Helping photographers learn to fish Supporting Member

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  9. sunbeam

    sunbeam TPF Noob!

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    Wow some great advice and good articles to read up on. Thank you everyone!
     

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