Complete Guide to Autofocus and AF Modes Part 3

If you are an enthusiast photographer, you know that autofocus and autofocus modes are one of the most difficult things in digital photography and it may take months to grasp these concepts. We already talked about autofocus types, AF points, and focus modes in Part 1 and Part 2 of our guides to AF, and today we are taking our explications further.

Learn everything about yet another AF concept which may seem confusing at first—AF Area Modes—that will help you reach perfection in focusing only on the most important in your photographs.

From our two previous articles in this series you found out about different autofocus types that were used in digital cameras throughout their short history and the importance of focus points as well as about the difference in focus modes that modern DSLRs let us choose from.

The concept that we are going to talk about today is called AF Area Modes and it should be applied together with the knowledge of focus points.

AF Area Modes can be used in both AF-S/One Shot AF and Continuous AF-C/AI Servo focus modes and are meant to provide you more precision in locking that focus up in the right spot—irrespective of how hectic your subject is—and shooting a crystal-clear picture. You can select the AF Area Mode with a selector or button on the camera body in professional DSLRs and in the menu in most of cropped sensor cameras.

Single Point AF Area Mode

This mode—called Single Point in Nikons and Manual AF Point in Canons—is great if you are making photographs of subjects that are not moving around and will come in handy in portrait, fashion, architecture, street, and landscape photography.

Acquisition of focus will be done using only one focus point which you will choose yourself by moving it up/down/left/right using the control toggle on your camera. Focus will be acquired through contrast detection only in this particular spot and will not be reacquired—unless you refocus once again—even if the subject moves.

Dynamic AF Area Mode

AF Area Mode that is called Dynamic in Nikons and AF Point Expansion in Canon cannot be used in AF-S focus mode but only in AF-C. Let’s expound a bit on this.

Remember we told you about the number of focus points that your camera—the sensor of your camera to be exact—is fitted with? It can be anything from 9 to 51 and some professional DSLRs that were released a few months ago have up to 150 focus points.

Okay then. This mode allows you to choose one focus point manually—just like in case of Single Point AF mode—and move it wherever you need around your photo using the control toggle. However, it also lets you select the size of the AF Area manually of 9, 21, or 51 focus points on Nikons.

This AF Area will surround your initial focus point and, when the focus is locked in the initial focus point and if the subjects moves, the camera will use the surrounding AF Area focus points and keep the focus where it should be by tracking how the subject is to move.

Mind though that you will still need to follow the subject with your initial focus point because if the subject leaves the chosen AF area, the focus will be lost. Some advanced modern DSLRs also have 3D Tracking AF Area Mode where the camera chooses the right number of activated focus point within the AF Area itself depending on the surroundings and the subject.

Dynamic AF Area Mode is great for doing animal, children, and sports photography.

Auto Area AF Mode

Auto-Area AF Mode in Nikons and Automatic AF Point Selection Area AF Mode in Canons are the most simple and complicated AF Area modes at the same time. Why simple? Because the camera chooses where to focus instead of you. Why complicated? For the very same reason.

Firstly, in this mode your camera will try to detect skin tones on your pictures and acquire the focus using them. If there are several skin tones in the frame—when you are making group photos or shooting the crowd—the camera will focus on the closest person.

If there are no people at all in the frame, the camera will automatically detect the closest and biggest object and will focus on it.

This mode may come in handy to those who are only starting their photography career, but it will definitely seem confusing to professionals because it’s really important to be able to control focus on your photos by yourself irrespective of the photography genre.

Group Area AF Mode

Group Area AF Mode is a novelty and available only on professional FF Nikon DSLRs. In this mode five cross-type focus points in the center of the frame will be activated at the same time in order to acquire focus. The focus will be acquired in the focus point where the closest subject to the camera is located.

The difference of this AF Area Mode from Dynamic AF Area mode is about precision and speed. The focus in Dynamic AF Area Mode will be automatically reacquired within the limits of the AF Area that surrounds your initial focus point only after the camera could not acquire focus in the initial focus point. In Group Area AF Mode there’s no room for error and the focus is acquired in no time in one of the cross-type focus points.

Check out this descriptive image from Nikon USA that shows you the way the AF Area Modes work. 

Single Point AF mode, Dynamic Area AF mode (9 points), Dynamic Area AF mode (21 points), Dynamic Area AF mode (51 points), 3D-tracking mode, Auto Area AF mode and Group Area AF mode.

Stay tuned for our next and the last article in this series on AF and AF modes where we will tell you about the most common situations in photography that require using this or that focus mode and AF area mode.

We hope that this article was of help to you and we’ll be glad to answer your questions in comments. Feel free to shoot us a message!

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