Camera Focus Modes explained for Beginners
Michael • updated January 2, 2023 • 8 min read
Michael • updated January 2, 2023 • 8 min read
If you’re just starting out in photography, you might be wondering what all those buttons and settings on your camera do. One thing you might be curious about is focus modes. But what are focus modes and why are they important?
In this article, we’ll go over the basics of focus modes and how you can use them to get sharp, in-focus photos. Whether you’re a beginner or an experienced photographer, you’ll find some helpful tips in this article.
So, let’s get focused (see what I did there?) and learn more about camera focus modes!
Before we get into how to focus and common techniques, you should know a few basic words and steps.
To learn how to take pictures, you need to know at least these things. It all starts with how the camera finds the focus on its own. And to be able to focus in a tiny amount of time.
As I said, you have to pick a plane of focus in space when you take photos. This is always in line with the lens and goes once across the whole photo. Depending on the aperture, the sharpness drops off faster or slower from there, depending on how wide the aperture is. But this razor-sharp point is really only sharp at one hundred percent.
By moving the focus on the lens, you can move the plane of sharpness back and forth. This is because the lenses inside the lens also move. The focus distance controls how far away from the lens the plane of focus is.
This is often shown on the lens with a scale. It can be changed by turning the focus ring in hand. Or, the built-in motor is used to move the focus lenses. This is called autofocus.
But autofocus is more than that. How does the lens even know how far to move the inner lenses to focus so that the desired spot looks sharp at the end?
The lens has a motor that lets it focus, but it needs to be told to move to a certain distance by the camera. The camera uses contrast as a guide to figure out how far away this point is from the “aimed” point in the viewfinder.
Unless you use Live View to focus, classic DSLR cameras use phase-detection autofocus. I don’t want to talk too much about how things work. At this point, I think it’s most important to know that this method usually works through a focus module. This works out the focus distance without using the sensor. Because of this, the later image is not always the same, even if the focus is perfect. This is why for example Sigma lenses must be calibrated first.
Another problem is that there aren’t usually that many autofocus fields, and the ones that are there are usually in the middle of the picture.
In addition to phase autofocus, mirrorless cameras can also use contrast autofocus. When an area of an image is sharp, it just means that the pixels next to it have very high contrast.
And the camera looks at this difference at the desired location. In simple terms, the lens then focuses until it finds a place with 100 percent sharpness contrast.
One thing to keep in mind is that most of the focus happens at the sensor level. As the camera focuses, the processor looks at the image for sharp spots all the time.
The benefit is that this can happen almost anywhere on the surface of the sensor. Faces can also be found with a little bit of computer magic.
Not only are there more options, but you also get the same level of sharpness in the picture that you saw when you took it.
Unlike phase autofocus, almost everything happens right on the sensor. No separate unit anymore.
The button on your camera that lets you open the shutter always has two stages. If you press it halfway, it turns on the autofocus. The picture is only taken at level 2 when you press it all the way down. This has been the factory setting for decades, and it still is.
In the meantime, though, there are better ways to do things. For example, it is usually best to separate the focus from the shutter release and set up extra buttons for eye autofocus or object tracking. We’ll talk about that soon.
The focus determines what the viewer will look at later. The focus is therefore an important creative tool for telling the story of your photo.
In reportage photography, for example, there are no rules. You focus on what matters at that moment. With a small aperture value like F1.4, at close range, the rest of the photo just fades out.
For portraits, the camera’s focus should be perfectly on the model’s eye. People also look other people in the eye during real encounters. T
his is something very human, which is why you want to look people in the eyes first. If this is not possible because of a blur, the portrait will seem wrong somehow.
If your model is slightly turned in and the eyes are not on one level, you should always focus on the front eye. If the back eye is a tad blurrier, it’s not as tragic as the other way around.
With landscapes, on the other hand, you want everything to be sharp. That’s why closed apertures are usually used for a high depth of field. To show everything important sharp from front to back, the hyperfocal distance is usually set as the focus.
Note that there are still limits to focus. For example, every lens is specified with a close focus limit. If you want to focus closer than this, it will not work. If you still want to see the image larger, you should check out my post on macro photography.
Now that we’ve got these things out of the way, let’s get down to the basics.
When it comes to autofocus, we need to get back in charge, just like we do when taking photos in general. Most cameras are set to let you focus anywhere in the viewfinder right out of the box.
Most of the time, the camera just focuses on whatever is closest to it. But there’s a problem if you want to pay attention to something far away. So, we now make it so the camera can’t choose a focus point on its own or can only choose from a certain area.
Note: Please check your camera’s manual to learn how to use all of the settings mentioned in this article.
Focusing on a single focus field, like the one in the middle, gives you the most accuracy. Even with phase autofocus, the central fields are often the most reliable because they usually have the best cross-type sensors. You can also change the size of the focus field on a camera that doesn’t have a mirror. The more precise, the smaller.
The good thing about this method is that you can really zero in on what you want. One problem is that the camera will start pumping if it can’t get the focus right at this point (for example, because there isn’t enough contrast). We have told it that it can’t just use the focus field next to it instead.
Still, this doesn’t happen very often, and the single focus field is still the best choice for most situations. Tips, I’ll show you what you can do with focus pumps.
This is called a zone focus, as the camera for example activates focus field only in the right half of the picturee. In other words, you restrict the camera’s movement while still giving it some room to move.
Depending on the camera, these areas are called the wide, broad, center, and so on. Most of the time, the square brackets [ ] show where the zones are. This way the camera can follow objects better than we could with a single focus area.
The zone focus can help you, especially when shooting athletes, running animals, or videos. If you’re just using eye-autofocus or object tracking, a zone focus also makes sense. We come back to this later.
Now that we’ve told the camera where to focus, we’re done. In the next section, we will talk about how the focus acts. Even though there are now some “smart” ways to do it, depending on who makes the camera, it always comes down to:
Autofocus Single, also called “One Shot” by Canon users, does exactly what it says: it only focuses once per photo. When you press the shutter button halfway, the camera focuses on that point.
As long as you keep your finger on the shutter button in this way, the focus distance will stay the same for a short time. After you take the picture, the game starts over from the beginning.
Continuous focusing is what Autofocus Continous (or AI Servo in the case of Canon) means. When the shutter button is halfway pressed, the camera doesn’t just look for the focus point once. As long as it is tapped, the distance is measured several times per second and the focus is tracked continuously.
This makes it possible to keep track of things like cars. During this time, the only thing that matters is that the chosen focus point stays on the object.
If you want to use manual focus, you have to turn the lens ring by hand. If there is an autofocus motor in the lens, it won’t move. In newer lenses, it only does this so that the electronic signals from the ring can be changed (focus by wire).
This type of focus is especially important for retro lenses that don’t have an AF motor. Also, even with an autofocus lens, there are many times when it’s better to focus manually.
For example, when using a tripod to take pictures of landscapes or products that don’t move. Or when the autofocus doesn’t work in backlighting, low light situations, or extreme close-up shots.
Now you know that autofocus is made up of a random AF area (or zone focus) and a command to focus on it for once or continuously. From this have come the following basic techniques:
The way to begin is to move the focus point to where you want the sharpness to be later in the picture. To do this, look through the camera’s viewfinder and tilt it until the image looks right.
For example, if the model’s eye is in the right half of the picture, you just move the focus point to one of the right focus fields above the eye. Then you just have to press the shutter button all the way down.
The good thing about this method is that there is almost no lag, so there is no room for error. In AF-C mode, you can also follow moving people.
To do this, just hold down the shutter release button and move the camera so that the focus field stays on the person. Then, when the time is right, you press the button all the way down.
If you have to change the focus field before every shot, it can sometimes get in the way of your work. So, with this method, you just leave it in the middle of the picture.
Most of the time, the advantage of centered focus fields is that they are cross-sensors, which are better at detecting differences. First, the focus point is put in the middle of the person’s eye, and then the shutter release button is pressed halfway and the you finally take the shot.
The picture can then be moved around while the shutter release button is still half-pressed. This is important because we want to use our own design, not just take photos from the center. If the picture looks good, just press the button all the way down.
The problem is that when you recompose the photo, you often shake a bit because of your own movement. Or just often, panning way too far.
This makes the stored focus distance move a little, which makes the image blurry, especially when the aperture is small. Before you make this your standard, have some practice.
The fact that the focus is completely changed before each photo is both a plus and a minus. This lets you make sure that every picture has the same sharpness. This is useful even if the camera itself is out of focus.
Focus and Recompose can only be used with AF-S. If you accidentally choose AF-C, when you half-press the shutter button, the camera will focus on the background as soon as you move the focus area away from the person to recompose the photo.
Modern focus modes in mirrorless system cameras offer a range of options that can help you get sharp, in-focus photos. These focus modes can be particularly useful when shooting fast-moving subjects, or when working in low light conditions.
One focus mode that is common in mirrorless cameras is continuous focus mode, also known as AF-C or AI Servo. In continuous focus mode, the camera is constantly adjusting the focus to keep the subject in focus as it moves.
This can be useful when shooting fast-moving subjects, such as sports or wildlife.
Another focus mode that is common in mirrorless cameras is single focus mode, also known as AF-S or One Shot. In single focus mode, the camera focuses on a specific point and then locks the focus until you release the shutter button.
This can be useful when shooting stationary subjects, or when you want to ensure that a specific point in the frame is sharp.
There are also hybrid focus modes that combine continuous and single focus, such as AF-A or AI Focus. These modes automatically switch between continuous and single focus based on the movement of the subject.
To use these focus modes, you’ll need to set your camera to the appropriate focus mode. This is usually done using a button or switch on the camera body. Some cameras also allow you to customize the focus mode settings to suit your specific needs.
It’s worth noting that the focus modes available on your camera will depend on the make and model of your camera. Be sure to consult your camera’s manual or online documentation to learn more about the focus modes available on your camera and how to use them.
Face autofocus and eye-autofocus are not the same. What you want is eye autofocus, which gives you more accurate results.
Not only eyes can be detected by analyzing the image content while focusing. Almost any other object can be focused on once and then tracked automatically.
A specific structure, such as a car license plate or a T-shirt print, can be detected here. The focus is now instructed to keep this element or pixel arrangement in view. The focus is then magically tracked in AF-C.
As a result, the camera automatically tracks the athlete, race car, or carriage, for example. It does not, however, perform as well as the eye-autofocus. The camera occasionally loses focus on the object. But it already works very well and has a lot of potential.
Practice. It’s the routine that allows you to take sharp photos even at F1.4 or f/1.8 especially with techniques like focus and recompose.
Beginner Photography Sections
Automatic focus is best compared to your eye. Your camera, like your eye, uses contrast in the image to make everything sharp. When the contrast difference reaches its maximum, the camera recognizes that the image is in focus.
Based on a few focus points, your camera determines which area to focus on. The total number of focus points is determined by the make and model of your camera.
If you put your finger on the shutter button, you’ll notice that you can press it halfway and all the way down. If you look through the viewfinder and press the shutter button halfway, your camera will focus with autofocus. You’ll usually hear a beeping sound when it focuses, and you’ll also see it directly in the image, focusing on a specific area in the photo.
The focus determines how far away the plane of sharpness in the image is. This is a very thin area with perfect sharpness due to appropriate contrasts. You will learn how to hit it easily and correctly in this article.
The autofocus motor moves individual lenses within the lens to achieve the proper distance setting. This information is received by the lens from the camera, which has previously determined the distance.
In most cases, a single spot focus field is recommended. This provides the greatest precision. Specific autofocus zones, especially for moving objects, make sense in the scenarios mentioned above.
The AF-S mode is recommended for stationary objects. Switch to AF-C mode as soon as you want to track moving objects.
For more camera type specific focus mode information look also at:
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