Single-frame af. The basics. Auto Focus: operating modes. Problems with auto focus

Continuing the conversation about how to learn how to take pictures with a DSLR, let's remember which picture we will consider “high quality”. Our picture must be correctly framed, that is, it must have organized boundaries and scale; the plot important part of it must be transmitted with sufficient sharpness at the selected depth of field (DOF).

In this article, we have already covered the features and methods of cropping as the first step to taking a photo. The next important step is to focus your DSLR lens on the subject you want to be sharp. The performance of the auto focus system is essential characteristic SLR camera, and is often the determining factor when choosing a brand or model DSLR cameras... Let's dwell on this in detail, because even small focusing errors will negate all further efforts, and simply ruin your footage.

Modern SLR cameras have two main focusing methods: automatic and manual. In both cases, the final action is mechanical movement of the optical unit of the lens: in the first case, the axial movement of the optical unit is provided by a micromotor controlled by the AF system, and in the second, by manual rotation of the focusing ring on the lens. Autofocus (AF) is used in most situations and can operate in several modes. Despite the clarity of focusing, the implementation of AF is rather complicated. technical challenge, for the operation of which special sensors are used. Simple models usually have one cross (most accurate) and 8-14 vertical AF sensors. AF sensors can work both separately and together, which is determined by the camera settings.

The camera settings allow the user to choose to focus on any of the sensors, or leave it to the camera's automation. In the latter case, the camera will focus on the closest or most contrasting object, which does not always correspond to the intention of the picture. Focus point selection in junior Nikon models is carried out by the selector on the rear panel; in Canon cameras, to select, you must first press the button under the icon, and in Sony camera- button Fn, and select Local AF mode. For details on selecting a focus point or area, refer to your camera manual.

Auto focus modes

AF-S(auto focus single) - AF mode, in which when the shutter button is “pressed”, the camera is focused and stops focusing. For Canon cameras, this is the “One-Shot AF” mode. Each time you press it halfway, the camera will focus again. This mode is used when the subject is stationary.

AF-C(auto focus continuous) in Canon cameras is the "AI SERVO" mode - continuous AF mode. When you press the shutter button, the camera continuously tries to focus on the subject. When the button is held down, the AF system continuously tracks focus. This mode is used when the subject (s) of the shot move or the framing is changed.

AF-A(auto focus automatic) - automatic selection of focusing mode. In this mode, the camera can choose to operate in either AF-S mode or AF-C mode. In Canon cameras, this is the “AI Focus AF” mode. Good mode for novice users.

M(MF - manual focusing) - manual focusing mode. Selected using a switch on the camera body next to the lens mount, or on the lens itself, or in the camera settings menu. In this mode, focusing is performed by turning the focusing ring on the lens by hand with control of focusing confirmation in the viewfinder and by the camera's sound signal. This mode on your DSLR will be very useful at night, in cases where the AF system is unable to focus due to low light levels, the presence of light sources in the frame, or a low-contrast scene.

Closely related to focusing is the depth of field (DOF), which is an expressive tool for both the amateur photographer and the master of photography when shooting a wide variety of subjects. Everyone has probably seen portraits with beautifully blurred backgrounds and landscape shots with superb sharpness throughout the depth of the frame. This will be discussed in more detail in the section on choosing exposure parameters. Now let's just remember one important rule DOF, which should always be considered when using both automatic and manual focus rivki. The rule is: the depth of field in front of the object in focus will be 1/3, and behind the object 2/3 of the entire length of the DOF.

Scene modes such as Portrait and Landscape directly operate on depth of field, in which the camera automatically sets the aperture based on a shallow depth of field for portraits and a large depth of field for landscapes.

AF lock and use of the center focus sensor can be useful in AF-S when accurate AF is required on an off-center subject. A typical example of such a situation is shooting a portrait, in which sharpness is usually established in the eyes of the subject. You can, of course, pre-select the focus point to the left or right of the center, but since the center AF sensor is cross-shaped, it is better to use it. To do this, you need to rotate the camera so that the central sensor is directed at an important detail of the subject, in our case, this is the subject's eye. When you press the shutter button halfway, the camera will adjust the sharpness, and if you do not release the button, this setting will be saved (AF will be locked) until the moment you fully press or completely release the button. While the shutter button is half-pressed, you can rotate the camera to change the position of the subject in the frame and release the shutter.

AF lock can also be performed by pressing / holding the AF-L button (AE-L, when assigned) and releasing the shutter release button, or pressing it multiple times to take a series of frames with the focus set. Different camera models have their own AF lock features, incl. and when taking a photo from video mode. Despite the initial difficulty in using this function, especially when moving from compact camera on the mirror, with a little workout, this action is performed mechanically. AF lock allows you to take full advantage of your camera's lens and sensor for exceptional detail.

In the dark, not all cats are gray or why do you need white balance

The camera "sees" colors differently than the human eye, which (together with the brain) is able to adapt extremely flexibly to different lighting conditions. This is sometimes the cause of frustration when viewing captured images on a monitor, and especially when printing on photo paper. The play of shades of color, so pleasing during the shooting, disappears somewhere, the colors become "cold", or vice versa, reddish with muted green. If the white balance is wrong, correction in the photo editor will not help, especially if the images were saved in JPG format.

For the correct display of colors in the picture, the camera must reproduce the white color exactly white, unless, of course, this does not contradict the idea of the picture. All digital SLR cameras have preset white balance (WB) modes for typical shooting conditions, such as a sunny day, light from incandescent or fluorescent lamps, etc. The most commonly used WB auto mode, which in modern models copes with most scenes, and for fine tuning, use the WB manual override. The WB setting is usually selected using the multi selector on the back of the camera.

For a start, it will be very useful to shoot in RAW format, which will allow, with further processing in a RAW converter, to correct both white balance and exposure and other errors inevitable for the period of acquaintance with a DSLR camera.

The settings of the exposure parameters and the choice of shooting and exposure metering modes, as well as the depth of field will be discussed in the continuation of this article.

Autofocus. However, accurate and fast focusing is unthinkable without the photographer's ability to work with points and focus areas. Often you have to shoot children or animals that now and then "run away" out of focus. And sometimes very precise focusing is required: for example, in front of the model's eyes when shooting a portrait.

How do I get the camera to focus in the right place?

How to work with focus points in different shooting situations? How to get the camera to focus on what you need? Let's figure it out.

It is important for a photographer to remember that a camera is a mechanism, although it is very perfect, but not endowed with reason. The machine's automation can recognize the type of scene being shot thanks to the metering sensor and work with focus accordingly. However, the camera cannot be aware of all the creative ideas of the photographer - it does not know exactly what you want to focus on in the frame.

How do I get the machine to focus in the right place? The camera needs to point to the point that should be in focus. This can be done by selecting areas and focus points. Focus point selection is available with both single-shot AF-S and continuous AF-C.

How do I select my preferred AF-area mode?

On entry-level cameras (Nikon D3300, Nikon D5500), AF area modes are selected via the i button menu. At the appropriate point, you just need to choose the best option.

Let's consider options for working with focus points. Each of them is beneficial in certain shooting situations.

Single point autofocus

Focusing occurs on a single focus point, which the photographer himself selects using the multi selector. The single-point AF (auto focus) mode gives him full control over focusing. This mode is especially useful for static scenes. These include landscapes, still lifes and portraits, if a person stands still, poses for us.

Single point focusing mode is usually used by default by advanced and professional photographers... It gives excellent results when working with high-aperture portrait optics: when we shoot with them at open apertures, the depth of field will be extremely shallow. Consequently, the slightest error with focus threatens that the frames will be simply out of focus.

If you need precise focusing with high-aperture optics, then it is easiest to achieve it when working in the single-point AF mode.

But this mode also has its drawbacks. If there is fast movement in the frame (frolicking children, animals, athletes), we may not have time to select the desired focus point, and the subject will simply "run away" out of focus. This is true even for continuous AF-C shooting, because when tracking the subject, it can easily go beyond the selected focus point, and sharpness will be lost. In such cases, the following AF-area modes come in handy.

Dynamic AF

This mode is only available with focus tracking (AF-C). In it, we select the main focus point in the same way as with single-point AF. But when focusing, the camera also takes into account information from other, neighboring focusing points. Thus, if the subject has moved away from your main focus point, the camera will still follow it based on the data from other sensors.

All modern Nikon SLR cameras, except for the simplest Nikon D3300, allow you to choose how many focus points will be used in tracking the subject - sensors on the entire frame area or located next to the point chosen by the photographer. The fewer points are used, the more accurate focusing will be, but the easier it is to lose the subject out of focus. And vice versa: the more sensors are involved, the more difficult it will be to lose the object out of focus, but the larger errors can occur when focusing.

Dynamic AF is great for capturing fast moving subjects. For example, birds in flight.

When working with dynamic AF, keep in mind that the main focus point will still be the one you have chosen. So for the most accurate focusing, you need to try to keep it on the subject being shot, not letting it go far from it.

3D tracking

This method, unlike the previous one, allows you to move the active focus point right after our hero automatically.

With AF-C focus tracking, the photographer selects the desired AF point. After that, if the subject moves, the camera uses the 3D tracking method, moving the focus point after it. This way, you will not lose focus even on a very fast moving subject. The most important thing is that the subject does not leave the frame. Otherwise, you will have to focus on it again.

In 3D tracking, the camera registers colors at the original focus point and then monitors their movement in the frame. Therefore, 3D tracking is most effective when the subject is different in color from the background. Otherwise, 3D-tracking may not produce the desired results, and the focus will "jump" to objects of similar color. Then you should use the dynamic or group AF mode.

Group AF

In advanced models of Nikon cameras (starting with Nikon D750) it is possible to select not one point for focusing, but immediately a group of simultaneously active points. Single-point AF allows you to accurately focus on focus, but sometimes it is not accuracy that is more important than speed. Focusing on a group of points is well suited for reportage shooting, motion shooting. It is also useful where the 3D tracking method fails (when the object and background are about the same color, when working in a dimly lit room).

Shooting action scenes in low light conditions is a real challenge for the photographer. Group AF is well suited for these conditions.

Automatic AF-area selection

By enabling this mode, you will let the camera automatics decide for themselves at what point in the frame you need to focus. But keep in mind: the automation does not know what exactly you want to focus on. Her opinion may not coincide with yours. Usually the automaton prefers to focus on the objects closest to the camera. It is not a fact that your heroes will become such. For the automatic AF area to work correctly, it is important that the subject is highlighted with contrast and brightness relative to the background. It is advisable to position the subject closer to the center of the frame. Also, do not overlap the subject with some kind of foreground (for example, shoot a portrait through the branches of a blossoming tree) - in this case, the focus will now and then "run away" to the foreground.

Focus Area Modes Available with Live View

We know that a completely different type of focusing works in Live View mode - contrast. Therefore, in this mode, you will not find the usual modes of operation with focus points. There are a number of interesting modes here, sometimes opening up new possibilities for the photographer.

One of the advantages of contrast focusing in Live View is that we can focus on any area of the frame, even at the very edge. To do this, it is enough to move the focus area to the desired place in the frame using the multi selector, and in cameras with a touch screen (for example, Nikon D5500) - with a simple touch. In the photo Nikon cameras we can set a certain size of the focus area.

Normal AF area is a small rectangle along which focusing takes place. Since the area of the rectangle is small, focusing will be very accurate. This mode, like the single-point AF mode, when working through the viewfinder, is great for shooting static scenes.

Nikon D810 / Nikon AF-S 50mm f / 1.4G Nikkor
When photographing with a shallow depth of field, focusing accuracy should be ideal. Normal AF-area mode is an excellent choice for this type of shooting.

Wide AF area suitable for faster, but coarser focusing: focusing occurs on the area that is larger. The wide AF area mode can be used where focusing speed is a priority - when shooting a reportage, recording a video.

The wide AF mode is appropriate when shooting shots with a large depth of field, when working at closed apertures. In such situations, perfect focusing accuracy is not required - a large depth of field eliminates focusing flaws.

A shot with a large depth of field. In this case, focusing over a wide AF area is quite possible.

Face priority AF- a function available only with contrast focusing. It is ideal for photographing people. Automation itself recognizes the face in the frame and will continue to follow it, even if the hero moves. This function is well suited for shooting reportage, for working with versatile zoom lenses. But if you shoot with high-aperture portrait optics, I recommend using the normal AF area mode for perfect focusing. Combined with continuous focus AF-F, Face-Priority AF is also suitable for action scenes with people (say, sports), because the camera itself will keep a person's face in focus.

If there are several faces in the frame, the camera will focus on the closest one by default. To focus on a different face, use the multi selector.

Difficulties can begin if the person periodically turns away from the camera or you shoot him from the back altogether. This often happens when shooting reportage, shooting sporting events... If the camera does not find faces in the frame, focusing will be the same as in the wide AF area mode - along a large rectangle.

Object keeping is another cool feature available in Live View. In many ways, it resembles the 3D tracking mode. In subject tracking mode, you must first align the focus area with the subject and press the center of the multi selector. Now the camera will follow the movement of the object in the frame.

Interestingly, the subject can be tracked in both single-frame AF-S and continuous focus AF-F. In AF-S mode, the device will keep the selected subject in the focusing frame, but it will focus on focus only at your command - when you half-press the shutter button. In AF-F mode, focus will remain constant. It is perfect for shooting action scenes! The only important thing to remember is that Live View focusing is more demanding on light than normal focusing. In low light conditions, it is best to use normal focusing through the viewfinder.

Konstantin Voronov

Professional photographer with ten years of experience. Has been working for six years teaching activities... A journalist by education, author of courses and educational articles on photography. Sphere of interests - landscape, subject, portrait photography.

When photographing, along with settings for aperture, ISO and image quality, one of the most important parameters for an SLR camera is the correct setting of the focus mode and method.

Nikon has many options for how focusing works through different combinations of focus modes and focus areas. Usually, focusing on modern Nikon DSLR cameras occurs when pressing the shutter button halfway, or by pressing the dedicated AF-ON button.

Focus modes:

‘AF-S’ or 'S' (Auto Focus Single)- focus mode cameras, in which the camera focuses when the shutter button is pressed halfway, and stops focusing when successful focus is achieved. Once pressed, once focused... In the manuals for cameras, the mode is often translated as ‘ Single-servo AF‘. To change the aiming accuracy, release the button and press it again. The mode is suitable for static scenes.

Focus mode switch to. The same is found on cameras, D1, D2, etc.

‘AF-C’ or 'C' (Auto Focus Continuous)- tracking continuous (continuous) mode of automatic focusing of the camera (in the instructions it is often translated as ‘ Continuous servo AF'). When you press the shutter button halfway, the camera constantly tries to focus correctly. I pressed the button - and the camera constantly monitors the focus... A very useful mode when subjects move or the composition changes.

This selects the focus mode on cameras by type, D4

AF-A (Auto Focus Automatic)- automatic selection of focus mode cameras... In this mode, the camera can choose to operate in either AF-S or AF-C mode. Basically, all amateurs shoot in AF-A mode and often do not even know about the presence of other modes. I noticed that the mode AF-A more often behaves like AF-S mode.

AF (auto focus)- general auto focus mode. The mode is activated on the camera itself, it should not be confused with the 'A' mode on the lens itself.

AF focus mode switch (lever) on the camera

MF(manual focusing)- manual focus cameras... The mode is activated using the camera menu. Usually only cameras without a focusing motor have this mode. In this mode, you need to manually turn the focusing ring on the lens to achieve correct focusing. On the one hand: manual focusing can be difficult for beginners, on the other hand: it is a vital focusing method for advanced photographers and professionals... Manual focusing on the CZK is one of the major advantages over conventional digital cameras (point-and-shoot cameras). Very often, the camera and lens automatics cannot determine how to focus correctly, and to achieve optimal focus, it is enough to switch to manual mode and manually tell the camera to focus accurately.

Focus mode switch via Nikon D5100 camera menu

M (M - manual focusing) - manual focus on the lens or on the camera... Same as MF. Attention: Not all lenses have a focus mode switch, for example, the lens does not have any focus switches at all. Important: To switch to manual focus MF with a lens that does not have a focus mode switch, you need to switch the focus lever to M mode on a camera with a focus motor; on a camera without a focusing motor, only MF mode with this lens will always be available. Different types of lenses and cameras are described in detail in the section.

A (Auto)- auto focus mode lens... When the focus switch on the lens is in this position, only autofocus with the lens is available. Attention: Not all lenses have such a focus operation switch, for example, the switch on the lens is shown below.

M / A (autofocus with manual override)- automatic focusing lens with the priority of manual control. Attention: Not all lenses have this focusing mode, the example below shows the switch on the lens. This mode assumes autofocus with instant manual focus override, while the lens does not need to be switched to the ‘M’ focusing mode. You can read more about this mode.

AF-F ( Full Time Servo Auto Focus) - Continuous tracking focus mode for video shooting. Attention: This focus mode is only available on modern cameras with video recording capabilities. This mode does not work when taking pictures. Usually you cannot find the mode in the menu. AF-F, it is only available in Live View when entering the info menu. This is a very useful mode, it allows you to record video with continuous autofocus. This mode is available only in cameras starting from.

Important: Due to the fact that all Nikon CCDs have different controls and different menus, each camera switches focus modes in its own way. V general case for the choice of the focusing mode M, AF, S, C is responsible switch near lens mount for cameras with a focusing motor and settings in the camera's menu. For non-motorized cameras, the focus mode is selected only through the camera menu... Various setting combinations for different types cameras are shown in the diagrams above.

Damn important: if you use a camera with a motor for focusing, and there is an autofocus lens on it but without a focus motor and without a focus mode switch on the lens itself, for example, a bundle (a camera with a motor) and a lens (without a focus motor and without a focus mode switch) - for manual focusing, be sure to switch the lever near the camera mount to the 'M' position, otherwise when focusing manually the camera can be damaged.

A number of Nikon cameras have a built-in rangefinder (focus indicator in the viewfinder). The rangefinder in the viewfinder can tell you which direction you need to turn the focusing ring on the lens in order to achieve correct focusing. The rangefinder works with both automatic and manual focusing. There is a rangefinder in cameras, etc. In general, on old lenses that could not focus automatically, there is a special focusing scale, which indicates the distance to the focusing object. It's a pity, when using old optics on younger Nikon cameras, the rangefinder refuses to work. With manual optics, the rangefinder works only on older Nikon cameras.

On any Nikon CZK camera, a green circle in the viewfinder in the lower left corner of the viewfinder is responsible for the accuracy of focusing on the selected focus point. When it is on, it means that the sharpness at the selected point is normal. The green dot (focus confirmation point) is an indispensable aid when working with old class lenses and the like, for example, such as

Advanced cameras have fine tuning of focusing operation: Release priority and Focus priority in AF-C and AF-S modes.

Typically in AF-C mode, the following choices are available:

FPS - the camera is more important than the shutter release, rather than focusing accuracy, this is called Release priority
FPS + AF frequency - the shutter is more important for the camera, but it also takes into account the focusing accuracy (not available on all cameras)
Focus - the focus is more important for the camera, not the speed of shooting.

Using the priority setting, you can set what is most important when shooting - focusing, and then releasing the shutter, or releasing the shutter and ignoring focus. I set AF-S priority to focus priority, AF-C to shutter priority.

Important note:

Live View

Live View allows you to turn a complex SLR camera into an ordinary soap dish, that is, you can focus (photograph) using the large display of the camera itself, and not through the optical viewfinder (peephole). In Live View, focus is based on contrast. This method much slower for normal focusing through the optical viewfinder. Moreover, the difference in focusing speed in Live View mode and through the optical viewfinder can be tens of times. Some cameras have two focusing modes in Live View mode. The first one is focusing "tripod", it is done as on usual digital cameras(dichotomously, in contrast). Second, you can frame the frame through Live View, but when you press the shutter button to focus, the camera turns off Live View, focuses through the usual focusing system, and then turns on Live View again or takes a picture. A simple description of how Live View works can be found in Dmitry Evtifeev's blog.

The settings are responsible for working with focus points. AF-area mode.

Automatic (auto-area AF), indicated as a white rectangle. Focuses on the closest subject using all available points.
Dynamic (dynamic-area AF), focusing works only on one point, but takes into account information from adjacent points
Single Point AF, focusing on one point only.
Additional: 3D-tracking, or selection of several zones. These settings are not available on all cameras and are often sub-functions of dynamic focus area selection.

Important:

It is very convenient to configure the selection of the focus area method for amateur and advanced amateur cameras using the soft key (as I did on). This will allow you to very quickly switch between single-point focusing, automatic area selection, dynamic mode, 3D tracking, etc. Nikon professional and flagship cameras have a special zone switch, which makes it easier to work with professional equipment.

Attention:

in manual focus mode (M, MF), only one focus point can be focused.

Important:

A number of cameras can show in the image on which point or group of points focus was made. When reviewing a picture, you can activate a mode in which the focus points will be indicated by squares. This mode is supported only by professional type cameras, and all full-frame ones. This is convenient because when setting up a quick preview of a picture at a scale of 1 to 1, the zoom is done exactly at the focus point at which the shooting was performed. This allows you to very quickly check and select good sharp images. On advanced amateur and amateur cameras, to view the correct focusing, you should hold down the zoom button, and then use the selector to find the area in the image for which focusing was performed. If your camera does not have a function that indicates which point was in focus, you can use the ViewNX software that comes with the camera. The focus points can be displayed on the computer display. This is sometimes very useful. In the examples of photos, I just copied the work of the ViewNX 2 program.

Important:

ViewNX only displays focus points on the computer when a picture was taken in AF-A, AF-S, AF-C with focus priority. If AF-S, AF-C with shutter priority is selected, the program will show focus points only if the camera was confident that the focus was correct.

Important:

Not all Nikon cameras allow you to change the area and type of focus when using the auto modes (green mode). V modes P, A, S, M everything can be customized to your taste.

Focus point loop function

This function simply allows you to move the focus point in a circle, thus looping it. When the rightmost point is selected, pressing the selector to the right will move the focus point to the leftmost position. This function simply allows you to work faster when focusing on one point.

Wide and standard focus area

Some cameras allow you to select a wide focus area instead of a normal one. Wide focus area reduces the number of focus points (areas). For example, with 11 focus points, 7 wide zones are created. Zones will be larger optically in viewfinders than dots. This sometimes makes it easier to work with the camera.

Focus adjustment (alignment)

Sometimes the lens may malfunction and focus behind the subject (back) or in front of the subject (front) in focus. People call this lack of lenses back focus, front focus (back and front focus). Some cameras may adjust to the “wrong” lens. To do this, you need to find the focus adjustment in the camera and correct the focus. Only, D500, D7500, D800e, D800E, D810, D810a, have adjustment, here.

Single-point focusing with the Nikon D2Xs

Cross-shaped focus points (sensors) vs regular focus points

How many times I didn’t use one-point focusing, I did not find the difference in the quality of focusing on the cross-shaped point and on the usual focusing point. Basically, cross-shaped focusing points (sensors) are said to do a much better job of focusing than regular focusing points. It is generally accepted that cross-shaped focus points are better at handling 'wire against the sky' scenes.

Focus illumination

Nikon cameras have a special light bulb that helps focus in dark conditions. The light bulb simply illuminates the subject to be focused and autofocus is easier to focus on. The backlight may not turn on in AF-C mode. The focus light is often referred to as a “spotlight” and is recommended to be turned off. Personally, I have the backlight turned off, but in poor lighting conditions I use a flash that has its own “red spot” with a long range. More details about the flashlight c.

Is everything complicated and little understood?

Then just turn on AF-A and the rectangular focus area icon. Automation copes well with basic tasks. I recommend fully automatic focusing for home use. Sometimes fine-tuning the focus point modes does not pay off.

Which Nikon camera focuses the best?

Conclusions:

Learning how to operate the focus modes will help you more accurately and quickly achieve the desired result. I highly recommend experimenting with the modes and focus areas on your camera.

23.07.2015 13542 Exploring the camera 0

Many aspiring photographers, first taking serious camera in the hands, have difficulty adjusting the focusing system. And the understanding that the autofocus mode must be chosen according to the condition that you are photographing is sometimes terrifying. I want to note right away that the autofocus modes and settings are approximately the same for different cameras from different manufacturers. They may differ in name, location, or be controlled in different ways, but the principle is the same everywhere. So what's the focus of autofocus? Let's figure it out!

First, you need to study the instructions for your camera, the "Focusing" section (this is how it is called in Nikon cameras, other manufacturers have options) and make sure that autofocus is enabled for your camera. On advanced cameras there is a separate switch on which there is an M (manual focus) mode and some other modes - different autofocus, or just AF.

Autofocus mode switch on the body of the "advanced" camera

Mode M (Manual) works in the same way as cameras worked in the pre-autofocus period. If your camera does not have such a switch on the body, then the autofocus modes on your camera are controlled through the menu.

In addition, motorized autofocus lenses also have an AF switch, very often labeled M / A - M. Make sure the lens is also in autofocus mode. Do not confuse the type of this switch with the AF-S autofocus mode, they are different things, although they have the same names.

Focus mode switch on the lens barrel

What are the autofocus modes

AF-A (Auto) ... Fully automatic mode, in which the camera "decides" for itself how to focus. This mode is absent in professional cameras; it is most often chosen by beginners who do not know which mode they need.

AF-S (Single) ... Mode for static, sedentary scenes. In this mode, the camera focuses once by half-pressing the shutter button to the middle, or the button, if your camera has one. The camera no longer focuses until you release the button. This option is preferred when shooting for landscapes and portraits.

In this case, in the camera menu in the autofocus section, from the focus or release values, I would recommend choosing "Focus".

AF-C (Continuous) ... Tracking mode, in which the camera continuously tracks the subject and adjusts autofocus continuously until you release the shutter button. Turns on when you press the shutter button halfway. This mode is activated when photographing sports events and sequential shooting.

At the same time, in the camera menu in the autofocus section, from the values of focus, release + focus or release, I would recommend choosing medium, release + focus, and if your camera has a separate AF-ON button, which you need to get used to using, then the release value.

Selecting Focus Modes in the Home Camera Menu

In addition, you still have to choose the type of AF area.

Autofocus Zones and Areas

Usually, the camera offers three options for focus areas, the adjustment of which is carried out either through the menu (in entry-level cameras), or a separate lever on the body of an advanced camera.

Selecting the focus area of a professional camera

Selecting the focus area in the amateur camera menu

White rectangle ... This is an automatic mode, the camera "decides for itself" which AF points to use. The focus is usually on the closest subject. If you are in doubt about which mode to use, then choose it. In AF-S mode, the AF points where the image is in focus will be highlighted, while in AF-C mode, nothing will be highlighted.

Crosshair ... This is a dynamic zone mode, it is used when photographing moving objects and requires further adjustment, which is described below. The crosshair works dynamically only in AF-C mode, in AF-S mode it is the same as focusing on a point, which you will learn about in a little bit below. In dynamic mode, you choose the focus point, and the further behavior of the autofocus system depends on the selected AF area (s).

Point... You simply focus on the selected point, and select the point with a selector, which you usually scroll through photos or a camera menu. Very handy when you know exactly what needs to be guaranteed in focus, such as the eyes when photographing a portrait.

The AF area for dynamic mode (crosshairs) depends on the specific focusing system of the camera, or rather, how many AF points are available in the camera. The more expensive the camera, the more dots. The RGB sensor is responsible for controlling the autofocus zones.

Regions can be conditionally divided into two types:

Multiple sensors (AF-Area). Focus information comes not only from the sensor you have chosen, but also from the points surrounding it, and the adjacent sensors in the viewfinder are not illuminated in any way. For example, in my Nikon D700 you can select a zone from 9, 21 or 51 points. Typically, the faster something moves in the frame, the more area is required.

3D tracking. This mode is used on different models with different focus areas, usually a crosshair or a rectangle. As the name suggests, this is a tracking mode that takes into account not only the distance to the subject, but also the contrast of the subject. You use the selector to select the focus point, focus the camera, and then focus begins to follow the subject if it moves, or you turn the camera.

The fundamental difference between AF-Area and 3D-tracking is that in the first case, the camera focuses on what falls into the selected autofocus zone, and in the second, the camera shifts the area behind the object by switching the autofocus sensors. This differs from AF-S in that AF-S is not aware if the subject moves farther or nearer during framing.

Plus, 3D tracking can even replace single focus point selection. Instead of going through the points with the selector until you get to the desired one, you can simply focus on the center in 3D mode and then frame the frame as you wish - the camera will keep focus on the subject, moving the focus point along the points. In this case, the subject will not be able to escape from autofocus. However, focusing accuracy cannot be guaranteed.

That's the whole focus of autofocus. All you need is photographic!

Details Updated: 28 May 2016

In this article, you will learn how to use autofocus, what modes it has, why the photo is “out of focus”, blurry, how to avoid it and how, accordingly, to make the photos as clear as possible!

Autofocus modes

First, let's talk about what autofocus modes are in most modern cameras (as well as in some phones and camcorders). So how do we set up autofocus ...

One-Shot AF modeCanon or "AF-S "yNikon)
Best suited for shooting stationary subjects or if you need to focus first, and then change the composition of the frame. When you press the shutter button halfway, the camera locks the focus until you either release the button or press it all the way.

Continuous AF mode (AI Servo AF forCanon or "AF-C "yNikon)

Good for taking pictures of moving subjects. Or if on the contrary - you are moving :) For example - if you are photographing from the window of a moving vehicle. While the shutter button is pressed halfway - the focus will change automatically depending on the movement of objects in the frame, autofocus will, as it were, "follow" these objects.

Intelligent AF mode (AI Focus AF forCanon or "AF-A "yNikon)

Used to automatically switch the AF mode. It is present in many SLR cameras and, in my opinion, is rather inconvenient - it is difficult to guess how it will behave, as a "tracking", or as a "frame-by-frame".

Manual focus mode

Usually, this mode is used - when the autofocus fails, or for special creative tasks. In order to focus manually (switch to manual focus mode), you usually need to use the corresponding switch on the camera lens (especially when it comes to a camera with interchangeable lenses).

Focus point / area selection

If you use autofocus, then in most cameras you can choose which part of the viewfinder (which "point") will focus.

Fully automatic focus and automatic focus point selection. In this mode, the camera usually focuses on the closest subject in the frame. In this case, the points that actually turned out to be selected for focusing will most likely be marked / highlighted in the viewfinder when focusing ends.
Center point focusing... This mode is available on most cameras, regardless of the manufacturer (Canon, Nikon and others), and is often present not only in DSLRs, but also in compact digital cameras.
The peculiarity of this focusing mode is that the camera will focus only on the object located in the very center of the viewfinder. This can be useful for more accurate focusing on the subject being photographed.
When choosing this type of focus, the photographer usually acts as follows: directs the center of the viewfinder to the subject being photographed, half-squeezes the shutter release button (on most cameras, this leads to autofocus blocking) and then uses the viewfinder to select a successful composition, being sure that his camera is well focused.
Focusing on a selected point.
When this autofocus mode is selected, focusing will be performed at that point in the viewfinder, which the photographer will point to. This dot is usually highlighted in the viewfinder. In some of the most modern cameras - to select the focus point, you can simply touch the appropriate place on the viewfinder screen. In most SLR cameras for this there is a joystick or buttons replacing it or a disk ("wheel").
How is this applied in practice? Let me explain! For example, when shooting a portrait, so that focusing occurs precisely on the eyes of the model - the photographer can choose the focus point - which is currently "superimposed" on the eye of the model, without this it may happen that the camera will automatically focus not on the eyes, but on the nose ...
Other options. The above are three main options for selecting focus areas. But each specific camera can have a greater number of options. Nikon cameras are especially diverse in this regard.

Autofocus and focus points.
We can see such a picture in the instructions for Nikon camera D7000

Autofocus illuminator

If the subject you are shooting is too poorly lit, then the autofocus illuminator comes to the rescue! In low light conditions (in the dark), the built-in flash of your camera will automatically open and try to diffuse the darkness! If you do not need it, turn off the autofocus illumination in the menu of your camera (you can refer to its instructions), or switch to manual focus mode (the focus illumination is often also turned off).

Problems with auto focus

"Why isn't he focusing?" "Why is it focusing in the wrong place?" Why is autofocus so slow? Such questions are asked by many novice amateur photographers!

In the manual for the Nikon D7000 camera there is a wonderful illustration showing scenes in which autofocus can show itself not from its best side.

Autofocus can be difficult in the following situations ...

In cases # 2 and # 5 - I recommend choosing the central focus point and trying to focus with it - EXACTLY aiming at the subject. Then, autofocus is unlikely to let you down! In other cases, if the selection of the center focus point does not help, you should switch to manual mode. However, for example, in my practice, difficulties in cases 3, 4 and 6 were extremely rare.

Alignment, continuous autofocus correction

But it also happens that even in favorable conditions, autofocus always focuses either a little closer than necessary, or a little further! Most often this "suffers" SLR Cameras especially after changing the lens. The reason may be in the lens, then you can adjust it a little at the service center. This adjustment is called "alignment". However, in some modern cameras, the function of adjusting / correcting focus for selected lenses is already built-in, and you can start it after reading the operating instructions first. However, this is not often necessary.

If anything in the above information remains unclear, please ask questions in the comments!

It might be helpful to read: