Auto focus settings

edited February 2015 Posted in » Nikon D5100 Forum
I have a D5100 and want to photograph birds in flight and need to know what auto focus setting and auto focus area to use. Thanks.

Comments

  • edited February 2015
    In my experience with the D3200, which I think is pretty similar in AF settings, I find the most reliable way to get birds in flight is with Continuous mode (or A mode which usually goes to continuous as it should) and dynamic area or 3D. It's best if you practice panning too.

    Dynamic focus settings are in effect when the shutter is halfway down.

    You basically have two sets of AF settings. A, S, and C determine whether a moving subject is tracked. In S, you choose a single focus point, and that is it. Use this when you have a stationary subject and when you want to focus and recompose. In C, if the subject leaves the initial focus point, the camera will try to track it. In A, the camera decides (usually pretty well) which of those two to use. I leave mine in A normally, but if going specifically for birds I'd put it on C.

    The other settings determine where focus begins and how it is tracked. In S, you choose one area and do not track. In Dynamic-area you choose one area to start with, and if your subject moves, the camera tries to track it. In 3D you also start with one spot, and the camera uses a more sophisticated program to follow a moving subject, including color information. Those two modes work much the same, but it seems that dynamic-area is less persistent but also less likely to jump to the wrong subject. Both are worth a try. I've had a little better luck with dynamic-area, but 3D can work well too, especially if the subject is prominent and easily differentiated from its surroundings.

    Edit to add: by the way, you'll also notice that in 3D mode the little red focus area light blinks. If your subject moves it should also tell you which focus point it has activated.

    Auto area mode takes control away from you. The camera decides what to focus on using all 11 points. If it chooses the right thing, it's nice and quick, but otherwise it's just wrong. Good for point and shoot, groups of people and wide scenic shots, but not for birds.
  • edited February 2015
    Adding a bit, the difference between dynamic-area and 3D can get a little confusing because both try to do much the same thing in very different ways.

    Dynamic-area locks on your chosen focus point, and if that area goes out of focus, it looks for changes in neighboring focus points. It's relatively primitive and fast, and pays no attention to content. It also tracks only subject movement, not camera movement. You cannot focus and recompose.

    3D uses more processing power, color and shape recognition as well as focus change. It's a bit slower, and sometimes is fooled by busy scenes, but it keeps track not only of subject movement, but camera too. Thus, in 3D when it's working right, it keeps focus on a chosen subject if either it or the camera moves. You can focus and recompose in 3D (as long as your subject is in a focus zone).

    3D is said to be very effective on cameras with many focus points, and less so on the low end ones with only 11, but it's worth trying.
  • edited February 2015
    Thank you Bruto for such a detailed reply. I was out yesterday putting you suggestions to work. Not much flying bird action where I was but will keep you posted.
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