Focusing can't be easy. Using any of the main shooting modes - auto, portrait or landscape - your camera does all the work for you. But it's too easy and not professional. It seemed simple, you just press the shutter button halfway, focus and take a picture. Then why do many pictures come out blurry and blurry? The answer is that the autofocus system does work, but not always the way we want it to.
Typically, in an entry-level or mid-range SLR camera, there are nine focus points that are scattered at a certain distance from each other.
There is always one AF point in the center, then two points above and below and three points each on the right and left sides, two of which are at the same level, and one is pressed to the edge of the frame. More advanced cameras have an additional six points, although these, unlike the first nine, cannot be selected manually.
How Autofocus works
To achieve autofocus when shooting in various camera modes, information from all nine AF points is used. The camera determines the distance from each part of the scene from the camera, selects the closest object that coincides with the autofocus point, and locks autofocus at that position.
This is fine and very useful if you want to focus on the closest objects in the frame, but it doesn't always happen that way, does it? Let's say you're shooting a beautiful landscape, but you want to focus on a flower in the foreground. What to do in this case? - In such cases, it is better to select manual focus mode.
Various focusing options
Automatic point selection
By default, your DSLR will use all AF points in each shooting mode, but you can often choose the focus points manually. Press the AF point selection button, specifically the button in the upper right corner of the back of the camera (location may vary depending on the camera brand) and an on-screen confirmation will appear that you are now using the Auto Select multi-point AF mode.
Single point focus mode
To switch between auto focus mode and manual focus, press the focus point button as in the previous step, but then press Set. The camera will now switch to using only one focus point. To return to multipoint mode, do the same.
Changing Focus Points
You are not limited to using only the center focus point in manual control mode. After switching to single point auto mode, you can use the arrow keys to select any other available focus point. To return to the center point, click the Set button again.
Focus Modes
The focus point guide works in any focus mode, so you can use one or more points depending on whether you're shooting a still or moving subject. Choose the most suitable focus mode.
When to use a particular focus point
Automatic selection
If you want to focus on the closest subject and need to react quickly to what's happening around you, Auto Select mode is a great option for you. This saves time, since in this case you will not be busy choosing one point or another, in addition, this mode is good for shooting moving objects.
Center focus point
The center focus point is the most sensitive to light and the most accurate of all, so it is great for use in very low light levels, or vice versa in very bright light. While using other points may lead to worse results. Center point is also ideal for situations where the main subject is in the center of the frame.
Top focus point
When you are photographing a landscape and it is important for you to emphasize distant objects and areas of the scene rather than the foreground, then it is best to use the top focus point. In this case, foreground objects will be more blurry, and objects located at a greater distance will be clear and sharp.
Focus point diagonal
Portraits turn out especially well when the subject is not in the center of the frame, but slightly to the side. When shooting a portrait, either horizontally or vertically, select the appropriate focus points located diagonally and focus on one of the subject's eyes. If your face is turned in at three quarters, then focus on the eye that is closest to the camera.
Boundary focus points
Focus points located on the far left and right sides of the frame are very useful in cases where you want to make the foreground more blurred and certain objects located further away at the edges of the image appear sharper.
How to Choose the Best AF Point
While for most of us, nine possible focus points will be more than enough, high-end cameras like the Canon EOS-1D X have an incredible 61 focus points. You can even select multiple focus points in small groups.
With so many focus points, choosing the best point can be difficult. It often seems easiest to use the center focus point, focus, then lightly press the shutter button to achieve focus.
You can lock the focus settings by holding the shutter button, compose your shot, and then press the shutter button all the way to take the photo. This often works, but it may not always be the best option.
The main problem with using only the center focus point is that the lighting information and the exposure value are set at the same time. That is, for example, you focus first on an object that is in the shadows, and then quickly switch to an object that is in the sun, then in this case the image will be overexposed.
Fix a point
You can press AE Lock, then compose your shot, allowing the camera to take into account constantly changing lighting conditions. While doing this, you should keep the shutter button pressed to keep the focus locked.
But it is usually easier to select an AF point that is closer to the area you need to focus on, so any subsequent camera movement will be minimal
Autofocus, including tracking, is a more preferable setting compared to manual focusing. In the hands of an experienced photographer, autofocus works much faster, and most importantly more accurately, than the average amateur photographer can do. However, autofocus is not as simple a thing as it might seem at first glance, but it should also be said that this is already quite a deep jungle, which does not go into right away.
Let's look at how to use autofocus, as well as those subtleties that will allow you to effectively manage it and get the best possible result.
To begin with, I recommend that you re-read the pages of your camera's manual that are dedicated to autofocus - this will be the best place to start. To properly perceive the material, you need to know and understand where the main controls for autofocus and focus points are located and how they operate.
Autofocus modes
Most cameras, including Canon and Nikon, are equipped with three types of modes: single, tracking and hybrid autofocus.
Single or spot autofocus
This mode is intended for photographing still scenes, such as portraits, landscapes, still lifes, etc. In this mode, when you press the shutter button halfway, the lens begins to focus on the object, which is located within the selected focus point. Once focusing is complete, the focusing operation is locked, allowing you to recompose the shot (focus is lost when the distance to the subject changes) and take the shot.
Understanding this topic, you need to understand that the lens does not focus on the subject, but at a certain distance. A very simple conclusion follows from this. If I focus on an object that is located at a distance of five meters, then, accordingly, all other objects located at a distance of five meters fall into the sharpness zone. In other words, after setting the focus and locking the autofocus, maintaining the distance to the subject, I can move the camera as I please, getting the composition I need, without losing focus.
This method is very good in cases where the distance to the object is quite large and measured in meters. At close distances, especially during macro photography, recomposing the frame, which may entail a change in distance by several centimeters or millimeters, leads to a noticeable loss of focus, which is even more critical with a narrow depth of field.
Autofocus tracking mode
This mode is also called continuous, it is simply irreplaceable when photographing dynamic objects - animals, sports, auto racing, etc. As long as the shutter button is half-pressed, autofocus works continuously, thereby keeping the subject in the sharpness zone. Naturally, autofocus does not lock, as in the previous version, which is due to the constant movement of the lens mechanism, which catches focus following the movement of the subject.
The obvious conclusion is obvious. In this shooting mode, you cannot change the composition. This is because autofocus reacts to the subject being in front of a certain focus point; if you change the composition, the subject will be lost and the focus will be on something else.
So, we understand what tracking autofocus is, now the last mode left is automatic or hybrid. It is designed to allow you to decide for yourself whether you need to lock autofocus or not. This mode, unlike others automatic functions cameras seems strange and useless to me, but this is my subjective opinion, perhaps someone will find usefulness and convenience in it.
Shutter or focus priority
For many beginners, the existence of such settings will seem surprising. But they exist and it’s simply impossible not to pay attention to them when examining autofocus. The first of the priorities (shutter) means that at the moment the shutter button is fully pressed, sharpness does not matter at all, in other words, control over this is completely entrusted to the photographer. This mode is enabled as standard for autofocus tracking.
Focus priority means that after pressing the shutter button completely, there should be sharpness at a certain or specific focus points. If there is none, then the camera will not allow you to take a photo. This mode is usually enabled at standard settings in single frame mode.
Contrast and phase detection autofocus, which is better?
In digital cameras, manufacturers use two types of autofocus, as you already understood from the name, these are contrast and phase autofocus. It will be very good if we understand these concepts.
Contrast autofocus system
This autofocus method is used in so-called digital point-and-shoot cameras and SLR cameras, but only when the “Live View” function is turned on. This type of autofocus does not require additional focusing sensors, since it uses exclusively the camera matrix to achieve focus. The image that comes from the camera sensor is analyzed by the camera processor for changes in contrast. If more precise focusing is needed, the processor commands the motor to slightly change the position of the lens lenses in any direction. If after this manipulation the contrast of the image decreases, then the direction of movement of the lenses changes to the opposite. The movement in the right direction continues until the contrast begins to drop again, having reached this limit, the processor tells the motor to return the lenses to the step at which there was maximum contrast. Having reached this value, focusing is considered complete.
As you understand, due to such peculiarities of autofocus operation (it is not known in which direction the motor should be rotated), many unnecessary movements are made. Which leads to the main disadvantages of this focusing method - low speed, which does not allow it to be used on professional cameras. The second disadvantage, perhaps not so critical, is increased energy consumption.
The advantages of this method are the simplicity of the design and the ability to focus almost anywhere in the frame.
Phase detection autofocus
As you understand, photographic equipment manufacturers have long answered the question of which autofocus to choose for us and themselves. Of course, the phase system won. Let's figure out why this is so.
This type of autofocus is used in digital SLR and film cameras. There is a slight interference in the optical image transmission system, so in addition to the main mirror, the camera is equipped with an additional mirror, which transmits part of the light to the phase detection autofocus module. Any light beam that passes through the beam splitting prism and microlenses is split into two beams, each of which is then directed to the autofocus sensor. If focusing is accurate, then the rays fall on the sensor at a strict distance from each other.
If the distance between the beams is less than the reference one, then the focus is closer than necessary (front focus).
If the distance is greater, then the sharpness is adjusted further (back focus).
In this case, the amount of shift indicates the distance from the ideal focus. Thus, the processor immediately receives data on which direction and how much adjustment is necessary.
Phase detection autofocus sensors can be cross-shaped or linear. Linear ones are also divided into vertical and horizontal. The latter are sensitive to vertical lines (tree trunks, fences), while vertical ones are more sensitive to horizontal objects (horizon, road). Accordingly, cross-shaped sensors are universal; they are sensitive to objects of any shape. You can find out which sensors and where they are located from the instructions for your camera, but the most sensitive sensor is located in the center of the frame.
The main positive quality of phase detection autofocus is its speed, which makes it indispensable when shooting dynamic scenes. The main disadvantages are complexity, bulkiness, the need for fine adjustment of all components, lower accuracy than contrast autofocus and a small number of focusing points.
Hybrid system
There is also a third type of autofocus – hybrid. From the name it becomes clear that this is a combined system, including the qualities of both systems described above. Such autofocuses are used in mirrorless and some DSLR cameras.
The essence of this system is that the sensors are mounted directly into the matrix. Thanks to this, focusing occurs according to the following system. First, phase autofocus sets the basic focus, and then, based on the received data, contrast autofocus begins to work. At the same time, the slowness of contrast autofocus is reduced by more than 75%. Phase detection autofocus does not require such precise alignment, and the entire system takes up much less space.
Having examined all the technical aspects of autofocus operation, I would like to conclude by saying a few more words about those factors that also affect its operation:
Lens aperture. Here everything is as always, the higher the aperture, the better the autofocus works.
Focal length. Everything here is quite confusing, but in a nutshell, the larger the focal length, the more visible any autofocus miss. In addition, there is movement, breathing and other factors. I conclude that the longer the focal length, the worse the autofocus works.
Image detail and illumination. The less detail and light there is in the area of the focus point, the worse the autofocus works.
The photographer himself, or rather your ability to use your equipment. If a person handles it skillfully, then everything works, but if it is careless and incorrect, then even the most modern autofocus system will miss.
The most important thing in your autofocus work is practice. The correct balanced approach to the operation of automation will give you the opportunity to focus quickly and efficiently. Which is exactly what is needed.
Happy photography!
Continuing the conversation about how to learn to take photographs with a DSLR, let's remember what kind of picture we will consider “high-quality”. Our picture must be framed correctly, that is, it must have organized boundaries and scale; the plot-important part of it must be conveyed with sufficient sharpness at the selected depth of field (DOF).
In the article, we have already looked at the features and methods of framing as the first step to taking a photograph. The next important step is to focus your DSLR lens on the subject you want to be sharp. The quality of the autofocus system is the most important characteristic of a DSLR camera, and is often the determining factor when choosing a brand or model of DSLR camera. Let's dwell on this in detail, because even small focusing errors will negate all further efforts and simply ruin your shots.
Modern DSLR cameras have two main focusing methods: automatic and manual. In both versions, the final action is the mechanical movement of the lens optical block: in the first case, the axial movement of the optical block is provided by a micromotor controlled by the AF system, and in the second case, the focusing ring on the lens is manually rotated. Automatic focus (AF) is used in most cases and can operate in several modes. Despite the clarity of focusing, the implementation of AF is a rather complex technical task, for which special sensors are used. Simple models usually have one cross-type (the most accurate) and 8 to 14 vertical AF sensors. AF sensors can work individually or together, depending on the camera settings.
Camera settings allow the user to choose any of the sensors to focus, 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 intent of the photo. Selecting the focus point in younger Nikon models is done using 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 the “Local AF” mode. For details on choosing a focus point or area, see your camera's manual.
Auto focus operating modes
AF-S(auto focus single) - AF mode, in which when you “press” the shutter button, the camera focuses and stops focusing. In Canon cameras this is the “One-Shot AF” mode. With each partial press, the camera focuses again. This mode is used when the subject is stationary.
AF-C(auto focus continuous) in Canon cameras is the “AI SERVO” mode - tracking (continuous) AF mode. When you press the shutter button, the camera continuously tries to focus on the subject. When you hold down the button, the AF system continuously monitors focus. This mode is used when the subject(s) are moving or the framing is changing.
AF-A(auto focus automatic) - automatic selection of focus mode. In this mode, the camera can choose to operate in AF-S mode or AF-C mode. In Canon cameras this is the “AI Focus AF” mode. A 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 achieved by rotating the focusing ring on the lens by hand with focus confirmation control in the viewfinder and by the camera's sound signal. This mode of your DSLR camera will be very useful at night, in cases where the AF system is unable to focus due to low lighting levels, the presence of light sources in the frame, or low contrast scenes.
Focusing is closely related to depth of field (DOF), which is an expressive tool for both amateur photographers and masters of photography when shooting a wide variety of scenes. Everyone has probably seen portraits with beautifully blurred backgrounds and landscape shots with excellent sharpness across the entire 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 of depth of field, which should always be taken into account when using both automatic and manual focusing. The rule says: the depth of the sharply depicted space in front of the object in focus will be 1/3, and behind the object 2/3 of the entire depth of field.
Depth of field directly operates with scene modes such as “Portrait” and “Landscape”, in which the camera’s automation sets the aperture based on a shallow depth of field when shooting a portrait, and a large depth of field when shooting a landscape.
Locking AF and using the center focus sensor can be useful in AF-S, when precise AF targeting is required on an off-center subject. A typical example of such a situation is shooting a portrait, in which the sharpness is usually determined by the eyes of the subject. You can, of course, pre-select a focus point to the left or right of center, but since the central 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 aimed at a plot-important detail of the object, in our case it is the eye of the person being portrayed. 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 you press or release the button completely. With the shutter button 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), releasing the shutter button, or pressing it repeatedly to take a series of shots while the focus is set. Different camera models have their own AF locking features, incl. and when taking photos from video mode. Despite the initial difficulty of using this function, especially when switching from a compact camera to a DSLR, with a little training this action is performed automatically. Using AF lock allows you to take full advantage of the camera's lens and sensor to capture exceptionally detailed images.
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 (along with the brain) is extremely flexible in adapting to different lighting conditions. This sometimes causes frustration when viewing captured footage on a monitor, and especially when printing on photo paper. The shimmering shades of color that were so pleasing during the shooting disappear somewhere; the colors become “cold”, or vice versa, reddish with muted green. If the white balance is incorrect, correction in a photo editor will not help, especially if the pictures were saved in JPG format.
To correctly display colors in a photo, the camera must render white exactly white, unless, of course, this contradicts the idea of the photo. All digital SLR cameras have preset white balance (WB) modes for typical shooting conditions, such as sunny days, incandescent or fluorescent light, etc. The most commonly used auto WB mode, which in modern models copes with most scenes, and for fine tuning, manual WB correction is used. Selecting the WB setting is usually done using the multi selector on the back of the camera.
To begin with, it will be very useful to shoot in RAW format, which will allow, during further processing in a RAW converter, to correct within a fairly wide range both white balance and exposure and other errors that are inevitable during the period of getting to know a DSLR camera.
The settings of exposure parameters and the choice of shooting and exposure metering modes, as well as depth of field, will be discussed in the continuation of this article.
We recently talked about how automatic focusing works in modern SLR cameras. But any type of focusing also has several operating modes. The photographer can choose from them the most suitable for a particular shooting situation. So what autofocus modes are there? When should you use which one? Let's figure it out...
How to enable the desired auto focus mode on your camera?
LET'S START WITH A SIMPLE: HOW DO NIKON CAMERAS SWITCH FOCUS MODES?
- First, make sure that autofocus is turned on at all. Check the switches on the lens and on the camera itself!
On the simplest models (for example, Nikon D3300 and Nikon D5500), it is important to follow only the switch on the lens. It should be in the AF position.
On advanced cameras, there are autofocus on/off levers on both the lens and the camera. The letter M denotes manual focusing. Accordingly, the abbreviations A (Auto) or AF (Auto Focus) denote automatic focusing. To enable autofocus, both switches must be in the appropriate position.
- Now that autofocus is turned on, select the desired mode.
On advanced cameras like the Nikon D7200 and higher, there is also a special button for selecting autofocus modes. It is combined with the autofocus on/off lever. You need to hold it down and rotate the rear camera control wheel. Although in words it looks a bit complicated, in reality this method of switching focus modes is very efficient. The engaged focus mode will be displayed in the viewfinder and on the camera screens (depending on the model - on the top and main or only on the main).
- Ready! You can now focus in the selected focus mode.
SINGLE FRAME AUTOFOCUS. AF-S
Single-shot autofocus, or AF-S (Auto Focus Single), can be called the main, basic autofocus mode. This is usually the default. In this mode, focusing occurs as follows:
Pressing the shutter button halfway activates the autofocus system;
The camera focuses at the point selected (by you or automatically), and then informs the user about this using a sound signal;
After this, the focus is locked at the specified position until the shutter button is pressed all the way (and the frame is taken) or simply released.
From this simple algorithm all the features of this mode follow.
- AF-S mode is good for shooting static scenes. Let's say you're photographing a landscape, still life, or a person posing for you. In this case, the focusing object does not move anywhere. This means you can focus on it once, and then calmly shoot or recompose the frame, keeping the shutter button half-pressed. Important nuance: After focusing has been achieved and the camera has signaled about it, you cannot change the distance between you and the subject you are shooting (approach or move away from it). This will cause the subject to be out of focus again. This is especially important when shooting portraits with high-aperture optics: there, even a change in distance of a couple of centimeters threatens to make the model’s face blurry. If, nevertheless, the distance is broken, all that remains is to refocus.
Nikon D810 / Nikon AF-S 50mm f/1.4G Nikkor
AF-S mode is great for taking posed portraits. The main thing is to remember that after focusing, you cannot change the distance between you and the subject, so as not to lose focus. After focusing, don't waste time - shoot right away!
- AF-S mode is not suitable for shooting moving objects. Since the focus is locked at a certain position after focusing, it cannot track fast-moving objects in the frame. But in our world there are quite a lot of them. These include frolicking children, animals, athletes, and all kinds of transport: bicycles, cars... It is extremely difficult to shoot moving objects in single-frame focusing mode: there will be a lot of focusing errors.
Nikon D810 / Nikon AF-S 18-35mm f/3.5-4.5G ED Nikkor
AF-S mode is great for landscape photography. It allows you to accurately select the required focusing point, after which the focusing will not “run away” anywhere.
CONTINUOUS AUTO FOCUS. AF-C
Focus tracking mode, or AF-C (Auto Focus Continuous), works differently. By pressing the shutter button halfway, you turn on automatic focusing. Now it will “follow” the subject at the selected focus point until the photo is taken or the shutter button is released.
Tracking autofocus is great for shooting fast-moving subjects. Use it to photograph sporting events, children's games, and frolicking animals. There is a ton of diverse movement in the world - don't miss it! Wherein modern technologies 3D tracking and dynamic focus point selection allow the automation to select the appropriate AF point. A separate lesson will be devoted to how to work with zones and focus points.
Continuous autofocus is not suitable for shooting with recomposing of the frame after focusing. A favorite technique of some photographers is to focus on the central focus point, and then, with the focus locked, recompose the frame as you like. This technique is inconvenient to use in autofocus tracking mode, because when the frame is recomposed, focus will be lost. The only option is to reframe the frame while holding down the AF-L button, which requires a fair amount of finger dexterity.
Nikon D600 / Nikon 80-200mm f/2.8 ED AF-S Zoom-Nikkor
It is more convenient to photograph animals of any degree of wildness with the AF-C focusing mode. This way they definitely won’t run out of focus at the moment of shooting!
AF-A MODE
The AF-A (Auto Focus Automatic) mode is available in amateur and advanced devices. In this mode, the camera’s automation itself determines which of the two autofocus modes (AF-S or AF-C) is appropriate in a given situation. The AF-A mode is suitable for beginner photographers: it allows you not to think about choosing an autofocus mode, the camera will make the choice for you.
AUTOFOCUS OPERATING MODES WHEN SHOOTING VIA LIVE VIEW
From a recent article on autofocus types, we know that focusing through the viewfinder and focusing through the Live View screen involve completely different mechanisms. When focusing through the camera screen, a type of autofocus called contrast autofocus is used. It has its own operating modes.
Live View mode: Shoot using the camera screen rather than through the viewfinder.
SINGLE FRAME AUTOFOCUS AF-S
This mode is similar to the mode of the same name, available when focusing through the camera viewfinder. When you press the shutter button halfway, the camera focuses on the selected point. Once the operation is successful, focus is locked until the shot is taken or the shutter button is released.
And here continuous autofocus AF-F works a little differently than AF-C. Focusing occurs not when the shutter button is half-pressed, but when it is released. That is, constantly. When the shutter button is pressed halfway, focus is locked. This method allows you to constantly monitor the subject of shooting, without losing sight of it for a second. We know that autofocus is locked in AF-S single-shot focusing mode after focusing by holding the shutter button half-pressed. But in AF-C mode this does not happen, and autofocus “follows” the subject to the bitter end. However, in both modes, the focus can be locked in the position in which it is currently located. For this purpose, there is a button to lock autofocus and autoexposure AE-L/AF-L (Auto Exposure Lock/Auto Focus Lock). So, by pressing this button, you will lock both the focus and exposure settings in the position they are in. However, in the camera settings you can independently specify what to block with this button - both parameters, only exposure or only focus.
So, we figured out the autofocus operating modes. But this is not enough to learn how to use the camera's automatic focusing system to its fullest! One important question remains: how do you tell the camera exactly what object you want to focus on? In the following lessons we will learn how to work with zones and focus points.