Focus Points

itskerstinyoitskerstinyo
edited April 2013 Posted in » Nikon D3100 Forum
I have had my Nikon D3100 for a pretty long time now. However, I continue to get discouraged due to the fact that I don't seem to truly understand the focal points given in the camera. I frequently have issues understanding the purpose of a horizontal and vertical focus point.

I read in some article that there is a different purpose for each focus point? I don't know what the purpose is and would like to find out.

I would like to know if this lack of knowledge is what's causing my pictures to not be completely focused. If I take a picture of a person, I want the whole person to be in focus and the rest blurred (using a 50mm f/1.8 AF-S lens). When focusing on the person I focus on the eye, but if I move to accommodate the composition will the area in focus be affected?

Thank you so much.

Comments

  • itskerstinyoitskerstinyo
    edited April 2013
    Also, I am shooting manual while doing this.
  • szlaszlo07szlaszlo07
    edited April 2013
    After focusing on the subject, do you move only the camera (to the left, right, up, down directions) or do you change the distance between you and the subject too?
  • itskerstinyoitskerstinyo
    edited April 2013
    I press half way and readjust by moving to the left or right sometimes. However, I don't move forward or backwards. Does moving side to side have an effect on the area of focus? Thank you so much by the way. Here is a link to my flicker account to see examples if you dont mind of course.
    http://www.flickr.com/photos/kerstphoto/
  • MooseMoose
    edited April 2013
    Howdy @itskerstinyo - Dealing with a shallow depth of field (short area in focus) can be tricky.

    If you're shooting someone on the street and you'd like for their whole body to be in focus, I would adjust the aperture to f/2.8. This will lengthen the DOF just enough so that the plane of focus is capturing the body of your subject and nothing else.

    It also helps to position your subjects so that there isn't anything directly behind them, like a brick wall.

    If you're shooting portraits of just the face, you can shooting between f/1.8 and f/2. Just be careful that small movements (either you or your subject) can through the focal plane (area in focus) on something else other than their eyes.

    To combat this, adjust the focusing mode to AF-S, compose your shot and then choose a focus point closest to their eyes without moving the camera.

    Hope that all makes sense and happy shooting! :)

    P.S. If you haven't already done so, check out my guide on using Focus Points and Focus Modes with the D3100.
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