Af options: which autofocus mode to choose?? Af-s, af-c,..

Cameras offer different autofocus options. It’s not easy to tell them apart. What are AF-S and AF-C? Which autofocus mode is the right one for which motive?

What is an autofocus mode?

Autofocus modes refer to the way in which their autofocus at focus on a subject behaves.

To start with, it is important to understand how autofocus works in general:

First press the shutter button halfway. This sends a signal to your camera to start focusing. Then press the shutter button all the way down. Your camera triggers a (hopefully focused) shot.

Autofocus Racing AF-C

autofocus mode tells the camera what to do when you press the shutter button halfway down. In other words:

Should the camera find the focus as soon as possible and then stop focusing?
Or is the camera supposed to find focus, but then keep focusing when the subject changes?

This is what autofocus mode is about.

By the way, there is another important mode: manual focus. It is not technically an autofocus mode and is therefore not covered in this article. But manual focus is an important technique to be familiar with. Because it can be useful in many situations.

There is no universal autofocus mode. The AF mode must be set correctly depending on the photographed subject.

What are the common autofocus modes?

If autofocus modes tell the camera what to do when you press the shutter button halfway down, which modes can you choose? And what do they do?

In general, there are two basic AF modes:

AF-S (aka single frame AF, single AF) and AF-C (aka focus tracking, continuous AF or servo).

There is a third autofocus mode, AF-A, also known as automatic focus, but it is not found on all cameras. It is a fully automatic mode with no possibility of intervention. We will come to this later.

Now let’s look at each AF mode in turn:

AF-S static autofocus mode AF-C

AF-S autofocus mode is often the default mode for photographers because it works in a very simple way:

When you press the shutter button halfway, the focus is locked on the area below your AF point. The focus remains locked until you release the shutter or take a photo.

In other words, when you press the shutter button halfway down and lock focus, this point doesn’t change anymore. Even if you are focusing on a bird that is flying away or on a car that is moving.

The focus point is fixed as long as the shutter release button is pressed halfway!

This is in contrast to AF-C, which I discuss in the next section:

AF-C Focus Tracking Auto Focus Mode AF-S

AF-C is a more complex autofocus mode. It works by continuously trying to lock focus on the subject as long as you hold down the shutter button.

So as soon as you press the shutter button halfway down, the focus starts to move. It can focus on a person, a rock, a wall, whatever. If the subject moves forward or backward under the autofocus point, the camera changes the focus point and follows it. Even if an object comes between the camera and the subject, the focus is recomposed. But this depends on other options that can be set, more on that later.

Note that in AF-C mode, your camera may constantly change the focus point to follow a subject. So this is interesting for sports photography, moving animals, car racing and the like.

AF-A is not available on all cameras; it is meant for photographers who are just starting out. It is virtually an automatic system that decides for itself which mode is the right one at any given moment. And that tends to go wrong. It basically switches back and forth between AF-C and AF-S depending on whether your camera detects a moving or a stationary subject.

I personally do not recommend the use of AF-A. because you don’t have the same level of control as with AF-C or AF-S. With AF-A you never know exactly what will happen when you press the shutter button. Because the camera may recognize whether the subject is moving or still, but it is not perfect at doing so.

When to use autofocus modes?

As I said above, I do not recommend using AF-A.

But what about AF-S and AF-C? When does it make sense to use these two modes?? This is very simple:

If you are shooting still subjects, use AF-S. And for moving subjects, use AF-C.

This way you can shoot at still subjects use helpful techniques, such as. B. Focusing and recomposing, where you focus on your subject and then recompose the image. This is especially interesting in portrait photography and when you focus on an off-center subject.

At moving subjects on the other hand, you can track your subject throughout the frame. The focus is then automatically tracked and the subject remains sharp in any case, even with a racing car.

Does this make sense? Well, what I suggested, with AF-S for still subjects and AF-C for moving subjects, will not always work perfectly.

For example, what if you’re dealing with a subject that’s mostly still, but occasionally moves?? How z. B. A bird foraging? For those moments when the bird is standing still, you should use AF-S so you can lock focus and take a series of shots. Also, you can always re-focus and re-aim if you need to.

However, for the moments when the bird is moving, you should use AF-C to get nice action shots. Of course, you can always switch between modes, but by then it may be too late.

Here is the solution: the AF-ON button.

What is AF-ON autofocus and when should you use it??

AF-ON button on Nikon AF-S AF_C

AF-ON button autofocus is an alternative method to focus with your camera. Instead of focusing by half pressing the shutter button, it happens with a button instead. It is on the back of the camera (AF-ON button).

Basically, you set your camera to switch the AF trigger from a half-pressed shutter button to AF-ON button.

The special feature of back-button AF is that it decouples the focusing mechanism from the shutter release button.

So if you want to focus and track your subject, you can press and hold the AF-ON button on the back while you shoot. But as soon as you want to lock the focus (i.e. when the subject stops moving), you can simply stop pressing the AF button.

Focus is maintained, and you can continue shooting with the front shutter release button.

For this reason, the AF-ON method is a common way for action, street, and wildlife photographers to focus.

However, this method is only useful to use if in the menu individual functions "AF-activated" specifies that autofocus is not activated when you press the shutter button, but only with the AF-ON button.

What is AF-lock?

AF lock is a setting that is offered on many cameras. It allows you to focus normally, but then lock your focus point even when you release the shutter button.

It’s a good way to keep the focus point whether you shoot with AF-C or AF-S. But I don’t recommend using them regularly. It is better to lock the focus by half-pressing (and holding) the shutter button or switch to back-button AF.

AF lock button

What are AF point modes?

AF point modes are the second main feature of autofocus systems.

Instead of telling the autofocus how to behave in the broadest sense, the AF-area modes determine the distribution of the AF-areas and how they can be used.

What this means? Autofocus points are simply points that can lock focus. Points can be active or inactive. So if you have an active autofocus point in the center of the frame and you press the shutter button halfway down, that point will focus on the object in that part of the frame.

However, if the center point is inactive, the autofocus system will completely ignore that point and use another (active) point to focus on.

Ideally, every point would be active and the camera would magically know exactly where you want to focus; and which autofocus points to use. Instead, you need to specify which AF points you want to use. Or at least you have to tell your camera to select the AF points by itself, which doesn’t always work well.

This is what AF point modes are all about:

You specify which points to use and how they should function. Now, different camera systems offer different AF point modes. So there is no uniform bandwidth of options, as is the case with the basic autofocus modes. But there are some common features, which I will explain in the next section.

What are the common AF point modes??

In general, there are three main autofocus field modes that are available on most modern cameras.

These are the AF-area modes you should be aware of, as quickly switching the area modes can be very useful when taking pictures.

Single point

Single field AF mode

The single-point autofocus point mode is a fairly simple option.

You use the camera buttons or joystick to select an AF point that you want to activate. And then your camera will focus only in this area.

Note that this is the most precise of the AF point modes, so I recommend this mode if you can take some time and focus deliberately.

A good strategy is to choose the center AF point, aim it at the part of the photo you want to be sharp, finally half-press the shutter button to lock focus, then recompose and take the shot.

By the way, there are other modes for single point AF fields; some cameras offer z. B. A mode where you can first specify which point you want to activate. When your subject moves, the surrounding AF points become active and you can continue to focus on the subject.

3D tracking

AF tracking algorithms are getting better and better, which means that tracking autofocus modes are becoming very popular.

in tracking modes, you can usually have your camera identify subjects in the image (based on many characteristics, including motion). Or you can select the first focus point. Then your camera will do everything it can to "stick" to the subject. And even if it moves around the viewfinder and even behind objects. By the way, at nikon this procedure is called lock-on.

AF tracking modes can also include a form of eye AF, where the camera identifies an eye and tracks it through the image. This is very useful for portrait, pet and wildlife photography.

I recommend using the tracking modes whenever you are confronted with moving subjects of any kind. And especially if your camera can handle complex movements. The tracking function is popular with wildlife, bird, and sports photographers, as it allows for sharp shots even when the subject is moving.

It should be noted, however, that AF tracking is not as precise as other focusing modes. And that dependence on the camera’s tracking algorithms can sometimes result in missed shots. This is especially true when shooting in difficult situations, e.g. B. In backlight or low light conditions.

Auto Focus

The auto AF metering mode works as you would expect:

You press the shutter button halfway, and your camera decides where to focus. In other words, you have no control over the AF points; that’s entirely up to the camera. In situations where you are not dealing with moving subjects, but don’t have time to focus carefully, automatic AF point modes are a good option.

But they can’t predict what they want to focus on, which means they often focus randomly, which is far from what they wanted to achieve. That’s why I generally recommend using a single-point AF point mode for still subjects and AF tracking for moving subjects.

autofocus modes: conclusion

Now that you’ve finished this article, you should know all about the different autofocus modes, including AF-ON button, AF-lock, AF-area modes and more.

And you should be able to select the right focus mode for the right situation. This way you will always get sharp pictures!

What are AF-area modes?

AF-field modes are ways to control the different autofocus points. They allow you to select individual AF points or instruct the camera to track the subject through different parts of the frame. It is important that you select the correct AF point mode for your shooting situation. Because that way, you can maximize the number of sharp shots you get!

What is AF-C compared to AF-S?

AF-C is a continuous autofocus that continuously focuses while you keep it active. AF-S, on the other hand, is a one-time autofocus, d.H. When you press the shutter button halfway down, the focus is locked; only when you release the shutter button can you refocus again.

What is the best autofocus mode??

There isn’t really one best autofocus mode; both AF-S and AF-C are good in different situations. AF-S is great for working with stationary subjects. AF-C, on the other hand, is perfect for tracking moving subjects in the image, as it instructs the AF system to continuously lock focus, even while taking photos.

What is the AF-ON button?

The AF-ON button activates an advanced method of autofocus that decouples the shutter release from the focusing mechanism. Instead, only the AF-ON button on the back of the camera can activate the autofocus of the camera. You just have to press the button on the back and your camera will start focusing. This is useful in situations where you want to focus continuously and then lock focus quickly.

What is the AF-lock / AF-L?

AF-lock function locks your focus point even when you take your finger off the shutter release button.

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