A&P Not sure if this is a nwebie question

Discussion in 'Lifestyle' started by ihkskim, Aug 20, 2007.

  1. ihkskim

    ihkskim OT Supporter

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    Is there a function where you can select which points you want focused? Reason why i'm asking is when I took pics of my car that was positioned at an angle, The focus point is nice and clear but towards the end it blurs out

    here is an eg

    [​IMG]

    if you notice the front wheel is in focus but the back wheels are not.

    i used d80 w/ 1.8 Nikkor Lens 1.8
     
    Last edited: Aug 20, 2007
  2. MeanFiddler

    MeanFiddler The C.I.A. is Trying to Kill Me

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    You need to use a smaller aperture to get a larger depth of field. I.E if you're using the lens at f/1.8 you need to try at least f/4 or f/5.6.
     
  3. e.pie

    e.pie Active Member

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    :werd:
     
  4. Derrict

    Derrict No, I am not Amish OT Supporter

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    generally speaking, yeah, those aperture works. the focal length also should be taken into consideration. when I use a wide angle lens (ie 16 35), I can shoot at f/3.5 and keep the whole car in focus; if I shoot f/3.5 with a longer focal length, the rear part of the car gets blurred out (distance from focal point, oof background).
     
  5. FusionZ06

    FusionZ06 /\__/\__/\__0>

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  6. mojito

    mojito New Member

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    well you can't just input the front and back of the car and think it'll work

    Things to do to increade DOF
    smaller aperture (larger number)
    wider angle lens
    increase camera to subject distance
    tilt/shift lens (best option, but $$$ and not very practical for most uses). This would allow you to change the focal plane to the same angle as the car, then you only need enough DOF for the width of the car.


    Also keep in mind how DOF works. Where ever you focus, of the amount of area in focus, 2/3 is behind, 1/3 in front. So if you focus on the very front corner, you're wasting 1/3 of the area. Instead focusing on say the closest corner of the windshield might work better. (Note this works for non macros, for macros the split is even 50/50).

    You can press teh auto DOF button on your camera (it stops the lens down tot he aperture you have selected to see how it will turn out, but the viewfinder becomes dimmer do its often hard to tell for sure.
     
    Last edited: Aug 21, 2007
  7. e.pie

    e.pie Active Member

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    I want to rent a TS lens someday to play around with :o
     
  8. Derrict

    Derrict No, I am not Amish OT Supporter

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    what works for me when using a longer focal length is focus on the center cap on the front wheel.

    When I use a wide angle lens, I'll focus on the front emblem.
     

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