Sharpness is one of the most important criteria for image quality. However, we often encounter its disadvantage. The reasons may be different, but the main one is the photographer’s mistake. In this chapter, I will talk not about sharpness as such, but about the reasons for its absence and how to deal with it.

Blur due to movement (shaking)

The most important reason for blur is movement, that is, blurring of the picture due to the fact that the photographer’s hand trembled at the moment of shooting. The result of the wiggle looks something like this:

It's a pathetic sight, you'll agree. The main factors causing the appearance of hair are given below:

1. Shooting in low light without a tripod or flash
2. Shooting at a long focal length (with a strong “zoom in”)
3. Shooting in motion, for example from a car window
4. Shooting fast moving subjects

If only one of the factors, a factor, is present in the shooting conditions, then it can almost always be dealt with. But if there are several of them at once, we are almost guaranteed to get a defective photograph.

For the first two factors (handheld shooting in low light, shooting with a long focal length), the “safe shutter speed” rule applies.

A safe shutter speed will most likely ensure that there is no movement. It depends on the focal length. Many sources provide a simple formula by which you can calculate a “safe” shutter speed - you need to divide one by the focal length. That is, with a focal length of 50 mm, a safe shutter speed will be 1/50 of a second. All this is wonderful and simple, but this rule does not take into account that the camera may have a crop factor, which narrows the angle of view and, as it were, increases the focal length of the lens. A 50mm lens on a 1.6 crop has an equivalent focal length of 80mm. How to calculate a safe shutter speed, say, for a focal length of 24 mm not cropped? You can't do without a calculator! I offer a simple but effective way.

We look at the lens focal length scale:

With a focal length of 24 mm, the next line corresponds to 35 mm. We calculate the safe shutter speed based on it, having first rounded the value up. Thus, a safe shutter speed for 24 mm on a 1.6 crop will be 1/40 of a second. We check it in the calculator - 24 mm * 1.6 = 38.4. That is, absolutely the same thing - a safe shutter speed of 1/40 second!

As the focal length increases, the safe shutter speed decreases proportionally. That is, for a 50 mm EGF, the safe shutter speed is 1/50 of a second, for 300 mm - 1/300 of a second. This explains why a telephoto lens without a stabilizer can only be used without a tripod on a sunny day.

Image Stabilizer (IS, VR, Antishake) makes life a lot easier, lengthening the safe shutter speed by 2-3 times. That is, a 300 mm telephoto lens with the stabilizer turned on allows you to take mostly sharp photographs already at a shutter speed of 1/100 of a second.

Of course, a lot still depends on the physical abilities of the photographer. Some people manage to get clear pictures at shutter speeds of 1/5 of a second without a tripod, while for others even 1/500 is not enough!

Shooting from a car window- very bad conditions that should be avoided at all costs. In addition to the fact that often shooting is done through glass (which does not add sharpness), the composition in such photographs is almost always absent. Purely documentary filming, but I have not seen a single artistic shot taken from the window of a moving car.

Shooting a moving subject can be solved in two ways - either with a very short shutter speed, or with an extended shutter speed with wiring.

We know that there are two ways to reduce shutter speed - opening the aperture and increasing the ISO sensitivity. To photograph fast-moving subjects (such as passing cars), you almost always need to do both. The picture looks static - the car seems to be standing still. To convey movement, a technique is used - shooting with wiring.

Photo by Sergei Tishin

Notice how wonderfully the movement is conveyed in the photograph due to the characteristic blurring of the background. How to do it? For shooting moving object with wiring You need to do some steps to set up the camera:

1. Setting the burst mode
2. Set the shutter priority mode (TV, S) and fix the shutter speed around 1/30-1/60 seconds. The longer the shutter speed, the more dynamic the background blur will be, but the risk of foreground movement increases. More speed - shorter shutter speed.
3. We switch autofocus to tracking mode.

When an object approaches us, we take it into the “crosshair” and begin continuous shooting, trying to keep this object in the center of the frame. Imagine that in your hands is not a camera, but a machine gun, and the object is a low-flying enemy plane that needs to be “shot down” :) The higher the burst shooting speed, the larger the series of photographs from which you can choose the most successful ones.

Blur due to optics

1. "Chronic" autofocus miss

The phenomenon when autofocus constantly tries to aim a little closer or a little further than necessary is called front focus And backfocus(respectively).

Most of all, front/back focus spoils the lives of those who like to shoot portraits, macro, as well as photographers involved in product photography. When shooting at close range, even a small autofocus miss significantly increases the defect rate. For example, we know that when shooting a portrait, the focus is on the eyes. Even if the focus confirmation point blinked in the right place, due to back focus the focus will actually be focused on the ears, and with front focus - on the tip of the nose (more serious misses are possible).

How to identify front/back focus? There are many options. First, use a special target to check autofocus. It looks like this:

However, such a target is only available in photo stores and you can mainly use it only when purchasing a new lens (or camera). The beauty of the target is that it is very easy to determine not only the presence of an error, but also its exact value.

Secondly, you can download plate for checking front/back focus take advantage of it. This can be done on the website www.fotosav.ru.

Well, and thirdly - the easiest option! Simply take a photo of a sheet of printed text, first focusing on a specific line or heading. In this case, you need to open the aperture to the maximum possible value and set the ISO sensitivity so that the shutter speed is no shorter than 1/100 (to eliminate shake). Take pictures from approximately this angle:

An arrow on a sheet of paper shows the line where autofocus was aimed. As you can see, in this case it worked correctly. To be sure, it is better to repeat the experiment 5 times.

However, sometimes it happens that all these five times the device focuses in the wrong place.

This is what it looks like front focus

And this is what it looks like backfocus

What to do if front/back focus is detected?

If front/back focus is detected when purchasing a lens, it is better to refuse such a copy and ask for another one - and so on until the test result suits you. But what if the defect is discovered after purchase?

Now some DSLRs have an autofocus micro-adjustment function, with which you can correct front/back focus without leaving home. However, most cameras do not have this function, so you will have to take the camera with all its optics for adjustment to service center. Yes Yes! All your equipment! If a technician “customizes” your device for a specific lens, it is not a fact that your other lenses will work as correctly as before.

2. Curvature of the image field

With most lenses, it is noticeable that the sharpness of the image in the corners of the photo differs from the sharpness in the center, and for the worse. This difference is especially pronounced at an open aperture. Let's look at the reason for this phenomenon.

When we talked about depth of field (DOF) in earlier chapters, we were talking about the space outside the lens, somewhere in the environment. But, do not forget that the depth of field zone is also on the other side of the lens, where the shutter and matrix are.

Ideally, the matrix completely falls within the depth of field (internal) zone, but the trouble is that the image field (marked with a dotted line in the figure) has not a flat, but a slightly curved shape:

It is because of this that the clarity of the image in the corners of the image will be lower than in the center. The saddest thing is that it is a congenital defect of the lens that cannot be corrected by any adjustments. It is known that a similar drop in sharpness in the corners of the picture is present in the Canon EF 24-70mm f/2.8L USM lens of the first version. In the second version of the lens, this drawback was eliminated, but this caused a significant increase in the cost of the lens.

3. Spherical aberration

Spherical aberration in photography it manifests itself as a softening of the image due to the fact that the rays incident on the edge of the lens are focused not on the matrix itself, but a little closer than necessary. Because of this, the image of the point turns into a blurry speck. This is especially noticeable when the aperture is open. At medium apertures, spherical aberration disappears for most lenses.

In portrait photography it gives interesting effect in the blur zone - the blurred background has a characteristic “twisted” pattern (bokeh). The picture itself, even in the sharpness zone, looks very soft.

Please note that the spots from light objects in the blur zone are not round, but slightly elongated, reminiscent of a cat’s eyes in shape. This effect is sometimes called “cat eyes”.

For decreasing spherical aberrations Aspherical elements are inserted into lenses.

4. Diffraction blur

From the previous paragraph it follows that to obtain the best sharpness you should close the aperture. Another question is to what value and is there any reasonable limit?

Let's look at an example. I just took three pictures of text on the monitor screen, Canon 50mm f/1.8 lens, shooting distance about 50 cm. Shooting was done with different apertures. Here is a 100% crop located near the center of the frame:

1. Aperture 1.8 ( a starting point). The sharpness is not so great; at an open aperture, spherical aberrations are strong, they soften the picture:

2. Aperture 5.6 (intermediate position)

It can be seen that the detailing has become much better than with the maximum open aperture! The reason for this is the reduction of the effect of spherical aberration. Well, that's already good. Can we assume that the further the aperture is closed, the better the detail? Let's try to clamp the aperture to the maximum!

3. Aperture 22 (aperture clamped to maximum)

What's happened? Why is the detail reduced so much? It turns out that the conclusion we made was premature. We have completely forgotten about such a phenomenon as diffraction.

Diffraction- this is the property of a wave to slightly change its direction when it passes an obstacle. Light is nothing more than an electromagnetic wave, and the obstacle is the boundaries of the diaphragm hole (aperture). When the aperture is open, diffraction practically does not manifest itself at all. But with a closed diaphragm, the waves propagate something like this:

It is clear that the image of a “perfectly sharp” point in this regard will turn into a slightly blurry speck. Exactly diffraction and causes a decrease in picture sharpness when the aperture is closed too much.

For most APS-C DSLR lenses, the graph of detail versus aperture ratio looks something like this:

In the vertical axis - the scores are the same as at school: 2 - bad, 5 - excellent.

It follows from the graph that maximum detail (in the sharpness zone) is achieved at apertures from 5.6 to 11. At a lower aperture number, the picture is spoiled by spherical aberrations, and at a larger aperture, diffraction spoils the image. However, this does not mean that you need to shoot everything with an aperture of 8. Often, the difference in detail is not so significant, but interesting artistic effects can appear with an open and closed aperture. With an open aperture, there is a pleasant softness in the portrait, good blurring of the background. When closed, there are characteristic stars around bright light sources.

Blur due to mirror clap

As you know, a mirror shutter, when triggered, causes a slight shake of the camera body, which under certain conditions can cause a slight loss of sharpness.

To avoid this, most DSLRs have a " mirror lock" or " preliminary mirror lift". Its essence is that to shoot you need to press the shutter button not once, but twice. The first time you press the mirror rises (the optical viewfinder turns black), the second time you shoot.

A very illustrative example is given in a short article on the website www.fotosav.ru, which compares two photographs taken without mirror blocking and with blocking.

The left fragment is taken from a photo taken in normal mode, the right one is taken with the mirror locked up.

The test involved a fairly old Canon EOS 5D camera; its shutter is really, really noisy and when it is released, your hands clearly feel the vibration. The shutters of modern DSLRs are more advanced in terms of vibration load, so the risk of such blurring of the image is much less. Some devices have a “quiet” mode, in which the shutter operates a little slower, but there is much less vibration and the picture is clearer.

Blur due to improper use of stabilizer

Stabilizer- a device that allows you to reduce movement when shooting handheld. However, sometimes it can cause harm.

The instructions for a lens with a stabilizer almost always contain a warning - turn off the stabilizer when shooting from a tripod. This rule is often neglected, but in vain. Have you ever brought a microphone to a speaker? After this, the amplifier self-excites and the speakers begin to whistle. It turns out exactly like the saying “much ado about nothing.” It's the same with the stabilizer. It is designed to counteract vibration caused by movement, but it does not occur on a tripod. However, the rotating gyroscopic elements of the stabilizer cause a slight vibration, which is perceived as movement and the stabilizer tries to dampen it, “swinging” more and more. As a result, the picture turns out fuzzy.

There is an opinion that the stabilizer can reduce the sharpness of the image during daytime handheld shooting. This may be true, but I don’t remember in my experience a single case where the turned on stabilizer would noticeably spoil the sharpness when shooting at a short shutter speed. Although, on the Internet they regularly write about the harmful effects of a stabilizer, for example, during macro photography. The arguments are as follows:

1. Reverse shake - the stabilizer reacts too strongly to slight camera shake and causes the image to shift in the opposite direction.
2. A noticeable jolt when the stabilizer is turned on causes the photo to become blurry. The stabilizer turns on when we half-press the shutter button (to focus) and works until the shot is taken. If you immediately press the shutter button all the way, then, indeed, the stabilizer can cause blurring of the picture. If you give the stabilizer a second to “calm down,” the risk of getting a blurry picture is reduced. Much also depends on the lens. For example, in the Canon 75-300 IS USM the stabilizer turns on with a clearly audible knock and causes noticeable vibration, while in the Canon 24-105L it is almost silent.
3. Microvibration from gyroscopes reduces picture clarity. Again, a lot depends on the lens - in cheap optics (Canon 75-300), vibration is indeed noticeable. The Canon 24-105L has virtually no vibration.

Personally, I prefer to turn off the stabilizer in cases where it is not needed, but mainly to reduce power consumption. The stabilizer really helps in cases where, when shooting handheld, the shutter speed becomes longer than safe and at the same time you don’t want to increase the ISO sensitivity. In other cases it is useless.

The stabilizer is also useless when shooting moving objects. It just compensates for the vibrations transmitted to the camera from your hands, but it is not able to slow down the movement of a running person who is caught in the frame. The stabilizer only helps when shooting static scenes. No matter how many steps of exposure the stabilizer compensates, with a long shutter speed moving objects will inevitably turn out blurry.

Incorrect image settings

In obtaining visually blurry images, not only the lens, but also the camera itself, or more precisely, its settings, may be to blame. In the image settings of the camera there is an item sharpness or sharpness, which determines the degree of contrast of the boundaries of objects in the photograph.

This setting is only relevant when shooting in JPEG. If you prefer RAW format, then the desired level of software sharpening (sharping) can be set in the program used to convert from RAW to JPEG.

With an increase in program sharpness, an unpleasant surprise may await us - an increase in the noise level. Look at two fragments of the same photograph, shown at 100% scale.

The first picture is from standard settings sharpness, on the second in-camera sharpening turned to maximum. The second picture is visually perceived as clearer, however, it is also noisier.

Test tasks

1. Learn to calculate a safe shutter speed.

2. Try taking a photo from a tripod with a long shutter speed with the stabilizer turned on and off, compare the results and draw conclusions.

3. Find the function in the instructions for your camera mirror lock and learn how to use it.

4. Try shooting the same scene with different aperture values ​​(from a tripod). Find out at what aperture your lens produces the sharpest image.

5. Try shooting in daylight with the stabilizer turned on and off (in the wide-angle position). Draw a conclusion regarding the advisability of using a stabilizer in good lighting and a short focal length.

Probably many have encountered a situation where on the small screen of the camera during the shooting process you see excellent, clear images, but after downloading to the computer they turn out to be cloudy, blurry, and sometimes all of them, and sometimes only partially. Where did the sharpness go? Why do photos come out blurry?? This article will show you some possible reasons.

Reason #0. TO good lens you get used to it quickly

This is a somewhat unexpected approach to the problem of lack of sharpness, but it is worth taking into account. Maybe this is exactly your case. Let's say you recently bought a new, good, expensive lens for your DSLR. Before this, you shot with a whale, but you saved up some money and now you can’t get enough of the quality of your photos.

Over time, you may forget how regular digital point-and-shoot cameras take pictures or what kind of photos you took with a kit lens. Then suddenly it happens that for some reason you shoot with your old soap dish instead of a good camera with a high-quality lens. When you view the resulting photos, you may notice that the picture from the point-and-shoot camera is “not sharp at all.” After agonizing thoughts regarding possible reasons, you guessed to look at old photos that you took with the same camera before buying a DSLR.

The results can be amazing. You see that your point-and-shoot camera has ALWAYS taken pictures so “unsharp”, but before you simply had nothing to compare with. Of course, a DSLR, and even with a good professional lens, will give a much clearer picture. Especially if you used a fixed focal length lens when shooting. The principle worked here - you are accustomed to good things, and what was previously considered good already seems mediocre, gray, “C”.

Acquaintance with photography most often begins with photographs of yourself, acquaintances, and friends. Over time, the genre “repertoire” expands. You start photographing flowers in the garden, neighbors' animals, nephews and nieces, friends' weddings. Products are on the table, after all. Expanding the scope of a camera's application is a long process. But there is a fundamental skill that needs to be developed all this time. It's about getting high-quality, clear images.

Naturally, each of us has a shot with excellent content, which, in the terms of a polite photographer, is “soft.” Or, to put it like it is - blurry and unclear. But, given the uniqueness of the situation captured in the photo, the frame will remain in our collection. And perhaps its poor clarity only adds to its charm.

Focusing– the fundamental principle of photography since its inception. Back in the early 1900s, it was a separate “craft.” However, in the 1960s, the legendary Leica introduced the first autofocus system to the public. This radically changed the order of things. Concept autofocus improved and today all cameras have such functions by default.

Modern digital SLR cameras (Digital single-lens reflex camera - DSLR), and not only them, have several automatic focusing modes. The trendsetters in this area are companies and. Other manufacturers are following the example of flagships. The names may differ depending on the brand, but the essence and principle of operation are the same. Therefore, we will look at the four main autofocus functions in Nikon and Canon DSLR cameras.

The photo above was taken using AF-S (Nikon) or One Shot (Canon) focusing. The center of attention is the model's eyes. The camera is focused on them. The photo itself is recomposed in such a way as to leave a little space on the right side, in the direction of view.

Single Shot Mode

Single focus- one of the oldest modes. In Canon it's called One Shot. On Nikon models - AF-S. Regardless of the name, the essence of how autofocus works is identical. The mode is used for photographing static objects. Regardless of whether they are alive or not. Models on set “freeze” most of the time, providing ideal conditions for focusing. The only rule for using this mode is that the subject should not move too quickly (or too much) in the frame.
To apply the mode, press the shutter button halfway (usually the camera beeps and changes the viewfinder display). After that, change as you see fit. For example, if you need to focus on the model's eyes, focus on her and then rotate the camera to place her on the left side of the image.
This mode is the most popular due to its simplicity. It works correctly in most cases.

Active or Continuous Focus Modes

Canon engineers called the next mode AI Servo. Their colleagues from Nikon preferred the abbreviation AF-C. The essence of the method is that the camera constantly monitors the movement of the initial focus point. And according to the change in position, the focus settings change. This feature is ideal for shooting moving subjects. For example, children playing, pets, transport - anything that is constantly in motion.

Auto Modes

And finally, the latest autofocus settings from the arsenal. We'll talk about AI Focus Canon and AF-A Nikon. Both modes leave it up to the camera to choose the best method to focus on parts of the image. The camera will either continuously track the subject if it is moving or go into single mode when capturing a static frame.
Theoretically, before clicking the shutter, you need to select the best autofocus option. The author must go into lengthy discussions about the specifics of the regimes. Not certainly in that way. The automatic mode in both brands works well and without unnecessary words.
The author of these lines tested these installations by taking still pictures of moving objects. The result is very good. The cameras choose the right focus settings, producing clear results. The statement is also true for stationary objects. The cameras detect the moment the movement stops and switch to “single mode”.
On the other hand, it’s still better to decide for yourself. Auto focus mode naturally has best qualities the modes mentioned above. But he also absorbed all their shortcomings.

The image above was taken using a standard 85mm f/1.8 lens in manual focus mode. This type shooting eliminates the risk of losing focus when changing the composition in automatic modes.

Thus, we have already managed to briefly familiarize ourselves with the three main automatic focus settings. Naturally this is not full list. In particular, Nikon boasts excellent 3D autofocus capabilities. Just like other SLR cameras are equipped with “ back button autofocus”, helping to focus more accurately on details. However, consideration of these topics is not the purpose of this article.

Manual Focus Mode

Now it’s worth focusing on the most rarely used focusing mode. This Manual Focus- manual mode. The thought of giving up automation instills fear in those who have never used it.
When is manual mode necessary? In cases where you yourself choose a clearer display area. This is creativity, the process of creating photographs and not recording an event.
Thus, if the task is to photograph children or sports events, autofocus will be the most justified choice. But when shooting still life, architectural monuments, landscapes and other relatively static objects, manual focusing opens up the horizons of creativity.

The simplest example is landscape photographs. Any autofocus mode concentrates on a single subject. In our case, it is necessary to increase the number of focus points to the maximum. That is, to achieve a large depth of field. Automation will only do harm here.
When photographing still lifes, photographers typically use a tripod. This is done with the goal of fixing the camera and focusing entirely on finding (or creating) the perfect composition for the shot. In addition, the stationary device facilitates the process of manual focusing.
There is another reason to use manual focus. And it was she who became the catalyst for the intention to write this article.

Take a close look at the photo above this line. The shot was taken using auto focus in One Shot/AF-S mode. Looks good. But if we zoom in, we notice that the eyes remain out of focus.
The author of these lines recently purchased a “” lens. And, naturally, I wanted to check what the sharpness levels are with an aperture number of f/1.8. Models served as subjects for shooting. Several shots were taken at f/1.8 in regular automatic modes (AF-S/One).
Upon closer inspection on the computer, it turned out that most of the frames were very “soft.” That is, with enough low levels sharpness. It took time to understand where the error occurred and how to correct the situation.

Look at the illustration above. The focal point is located in the central part of the viewfinder. This is despite the fact that I need a wider size when shooting a portrait.
The author did not have much experience shooting in shallow focus before this test. And now I have the opportunity to see the results of using this technique. Lenses with an aperture number of f/1.8 have a very, very shallow focus (depth of field). For example, when shooting a head with focus on the eyes, the nose already turns out blurry.
For testing, the model was filmed at 3/4 of its height. The distance to the photographer is about 2 meters. The focus point was placed on the girl.
The problem with most cameras is that although they have multiple focus points, they are all concentrated in the center of the viewfinder. And the choice of external (distant from the center of coordinates) entails a significant change in the composition (rearrangement) of the frame.

The picture above shows what actually happens when you change the composition to find focus points in auto mode (AF-S/One). In short, the part of the image where the initial focus was set falls out of the focus area.

When using lenses with an aperture of f/16, this problem is not particularly noticeable. But at an aperture of f/1.8, a shift in the focal plane automatically leads to a “softening” of other important areas. An example is an illustration of the “soft eyes” of a model. Rearranging the frames resulted in the focal point moving to the background of the girl. That is, the back of her head and her hair came into the spotlight and turned out sharp. But the eyes are the opposite.

There are probably no algorithms to solve this problem within the framework of “automatic modes”. You won't even notice the focal plane shift on the camera's small monitor.
The only option that really helps is switching to manual focus mode. In this case, you can manually focus on the model’s eyes and other areas of the image that should be sharp.

Of course, when shooting models, a confluence of factors occurred that aggravated the problem.
Firstly, shooting was carried out at an aperture of f/1.8. This always means critical sharpness values.
Secondly- I shot from bottom to top. This always leads to an increase in focal plane shift when the frame is recomposed.
And finally, there is the problem of limited focusing points. There are many reasons why modern DSLR cameras do not place focal points at the edges of the viewfinder.
It’s a paradox, but many “compacts” (mirrorless cameras), as well as micro cameras, have the ability to set the coordinates of the focal points. Unfortunately, this technology is not available in DSLR cameras. Therefore, take advantage of autofocus where it gives results and feel free to switch to manual mode for precise focusing.

There is no established definition for the term wiggle. In this context, we will assume that this is image blur when shooting a static object, caused by camera movement (shake). Camera instability is usually caused by rough pressing of the shutter button or shaking hands. To to avoid stirring at handheld shooting there must be endurance Briefly speaking, how

where EGF is the equivalent focal length (equivalent to 35 mm film). For the Canon EOS 400D, the crop factor is 1.62, then EGF = f*1.62, where f is the focal length of the lens (usually indicated on the front). For example, for f=55 mm EGF=(55*1.62)=89 mm (maximum focal length of a kit lens). In this case, when shooting handheld, the shutter speed should be faster than 1/89 second (for example, 1/125 s).

In order to reduce shutter speed you have to shoot at wider apertures or increase the ISO. By the way, increasing the sensitivity of the matrix (ISO) is not always bad - it’s better to get sharp image, albeit a little grainier than smeared (Fig. 1).

Canon 300D, f=50 mm, EGF= 80 mm, f/8, handheld shooting ISO 100.1/ 25 s, image blurry ISO 400, 1/ 100 s, image sharp Rice. 1. At ISO 100, the shutter speed was 1/25 s, condition Tv< 1/ЭФР не выполнено — кадр получился смазанным. Увеличение ISO до 400 единиц позволило сократить выдержку до 1/100 с (в 4 раза) и избежать "шевеленки" — кадр получился резким

Note: When shooting handheld, you need to press the shutter smoothly! Much like how Olympic shooting champions pull the trigger. Only the trigger finger moves; the camera must remain motionless. In addition, I will give recommendations from J. Wade’s book “Landscape Photography Techniques”: “Stand relaxed: legs slightly apart, weight evenly distributed on both legs, camera at the eye and elbows tightly pressed to the body. Focus the lens, hold your breath and slowly press the shutter release, concentrating only on the movement of your finger. Do not take a deep breath or hold your breath while focusing and framing. Breathe normally and only hold your breath briefly when you press the shutter release."

Addition from Eugene Glushko (connected with a move from shooting practice). Sometimes a movement (miss) occurs due to hasty lowering of the camera (rifle). To avoid this, shooters are recommended to keep the target on the front sight for a few more seconds after firing, without changing their position. Photographers are also advised not to sharply lower the camera, but to hold their gaze slightly in the viewfinder. When it is not possible to use a tripod (or monopod), you can use various kinds of supports - a parapet, the back of a bench, lean against a tree, sit with your hand on your knee, lie on the ground. In general, what the conditions and the plot allow.

Funny link from barinvic (from the HE forum): http://www.metacafe.com/watch/1041948/1_image_stabilizer_for_any_camera_lose_the_tripod/ - this is a short video (96 sec), where a guy uses a device in the form of a rope with a screw and a ring instead of a tripod. The ring is pressed with your foot, and the screw is screwed into the camera (into the tripod socket). Before taking the photo, he tightens the rope. I haven’t tried it myself yet, if anyone tries it, please tell me about the results.

2

The subject is moving - shutter speed is shorter

If the subject is mobile, then to get a sharp photo you need short excerpt. Usually, when shooting a motionless person, the shutter speed is set to no longer than 1/60 s; for a fast-paced child, even 1/200 s may not be enough. And to “freeze” movement in sports you need 1/500 s or shorter.

Sometimes to achieve artistic effect blur (motion effect) is specially made with a long shutter speed (Fig. 3).

Note: blurring a fast moving object in the frame depends not only on the shutter speed, but also on the type of shutter. Most modern DSLR cameras use a curtain shutter. Despite the fact that it allows you to achieve very fast shutter speeds (for example, for the 400D the minimum shutter speed is 1/4000 s), when shooting a fast-moving subject, it suffers from distortion. The fact is that the curtains always move at the same speed, regardless of the shutter speed. Shutter speed is determined by the delay between the movements of the first and second curtains. At short shutter speeds (shorter than 1/200 - 1/250 s), the second curtain begins to move before the first one reaches the end - exposure occurs through a moving slit between both curtains. As a result, a moving object has time to move in the frame from the start of exposure to its end, which can lead to its distortion. Such distortions are barely noticeable and do not play a role in normal photography.

To reduce this limitation of the curtain shutter, some digital cameras use an electronic shutter, which is not a separate device, but the principle of dosing exposure with a digital matrix. The shutter speed is determined by the time between zeroing the matrix and the moment the information is read from it. Using an electronic shutter allows you to achieve faster shutter speeds (including flash sync speeds) without using more expensive high-speed mechanical shutters. An example is the Nikon D70/D70s/D50 cameras, whose combined electronic-mechanical shutter allows you to shoot in flash synchronization mode (X-sync) at shutter speeds up to 1/500 s. For comparison: Canon 400D has an X-sync shutter speed of 1/200 s, Canon 30D has 1/250 s, Canon 1D Mark III has 1/300 s, Canon 1D has 1/500 s, Nikon D80 has 1 /200 s, for Nikon D3 - 1/250 s.

3

Incorrect camera settings - check the Sharpness setting

Check in settings camera value sharpness parameter(Sharpness). It should not be equal to the minimum value (Fig. 4)!

For numbers it is always necessary sharpen. An anti-alias filter is installed in front of the matrix, which specifically blurs the image a little (see Dmitry Rudakov’s “Sharpness... without a tie”). At minimum parameter value Sharpness the picture will be very " soft" (Fig. 5). Typically, this setting (zero for the 400D) assumes that sharpening will be increased more accurately with further processing of the image.

Rice. 5. The influence of the Sharpness parameter when shooting in JPEG: Canon 400D, EF-S 18-55, f=18 mm, f/5.6, 1/400 s, ISO 100

Attention! The sharpness setting only affects the JPEG output by the camera (not RAW!). But at the same time "native" RAW converter reads the parameter value Sharpness from EXIF ​​and uses it as initial installation(at least for Canon cameras).

Above we discussed the so-called sharpening in water(Capture Sharpening). For digital, this is conversion from RAW (when shooting in JPEG, this is done by the camera itself). In addition, sharpness has to be increased when conclusion(Output Sharpening). This includes preparing the image for printing (for example, for inkjet printer you have to “sharpen” more than for a minilab), as well as reducing the image for publication on the network (displaying it on the screen). Bruce Fraser, renowned specialist in digital processing, highlights third stage - selective sharpening (Creative Sharpening). For example, in a facial portrait, to focus attention on the eyes, they are usually made a little sharper. We will leave these and other issues of sharpening during image processing for a separate article.

Note. A filter in front of the matrix that slightly blurs the image is often called anti-alias or optical low-pass filter. This term is used not for its intended purpose, but rather by analogy. The filter itself serves to reduce color artifacts and moire in mosaic matrices (using the Bayer pattern) and more plausibly convert a monochrome RAW image to color.

It should be noted that cameras from different manufacturers have different degrees of influence of the anti-alias filter. For example, it was noticed that Nikon’s filter blurs the image less than Canon’s. From here you can often hear “the ringing sharpness of Nikon” or “Nikon D80 is sharper than Canon 30D”, etc. This doesn't mean the Canon is any less sharp. It’s just that to achieve Nikon’s level of sharpness on Canon, you will have to set a higher value for the Sharpness parameter. By the way, Canon has three low-pass filters in front of the matrix.

Some cameras don't have an anti-alias filter at all, like the Leica M8. But there is a price to pay for this. When examining the image with the Leica M8 in detail, roughness appears in some textures, as well as in the out-of-focus zone, as if the photo was taken through some kind of grid (and this is at low ISO, when noise is minimal!). For some low-pass cameras, the filter is “turned off” optionally, for example, Mamya ZD.

It is also worth mentioning the three-layer Foveon matrix. Unlike a mosaic pattern, here each pixel is “honest” and captures all three components of color (RGB). Theoretically, such a matrix gives the sharpest picture and provides the most accurate detail at 100% image scale. To date, this technology has hardly been developed and is represented by the only camera produced, the SIGMA SD14 (resolution 2640x1760 - 4 megapixels).

4

DOF is small

DOF - depth of sharply depicted space. Unsharp pictures may be subject to small depth of field. For example, for a kit lens at the long end of f=55 mm at f/5.6, the depth of field will be about 7 cm (at a distance to the subject of about 1 m). Accordingly, objects outside the depth of field will be blurry.

This blurriness is usually complained about by those who are used to photographing with a digital compact, which has a large depth of field and all objects are in the sharpness zone. Shallow depth of field is one of the advantages of cameras with a large sensor and is usually used for artistic purposes to give the image volume. A blurred background allows you to “separate” the subject from the background (Fig. 6).

Most will agree that it is convenient to use the central focusing point: point the center of the viewfinder at the subject, focus (press the shutter halfway), then compose the frame and take a photo (press the shutter fully). However, there is a pitfall here: camera rotation when cropping can lead to loss of sharpness on the shooting object (Fig. 7).

Rice. 7. Framing by rotating the camera can lead to loss of sharpness on the subject

There are a few ways to avoid this error:

• select focus point manually(but this is not very convenient: spin the wheel every time);
• don't turn the camera, but displace parallel to the plane of the subject;
• use manual focus(MF);
• increase DOF by closing the aperture (but this reduces background blur).

Note. In fact, the autofocus sensor units are somewhat larger than indicated by the mark in the viewfinder. This can be illustrated simple example: draw two lines on a white sheet - one thin, the other thick (see Fig. 8, a). Let's place the camera at an acute angle to the sheet, the lens axis is perpendicular to the lines. If, when pointing along a thin line, a more contrasting, thick line ends up outside the mark in the viewfinder (red frame), but within the sensor area (indicated in green), then the camera can focus along this contrasting line (Fig. 8, b). Such normal operation autofocus is often regarded as back focus. If only one contrast detail remains in the area of ​​the autofocus sensor, then “false” back focus does not occur (Fig. 8, c). This is why you cannot test for back focus by photographing a ruler - the scale must be located at some distance from the target.

Rice. 8. A fragment of a photo explaining how autofocus works: red indicates the frame in the viewfinder, green indicates the actual size of the autofocus sensor

5

The lens is soapy - close the aperture or change the lens

This is the case when resolution lens lacks for a sharp image. The smaller the pixel of the matrix, the stronger the “soapiness” of the optics. For example, at 400D photosensor size 5,7 µm, and y 300D photosensor 7,4 microns (which is almost 1.7 times larger in area!). Accordingly, when shooting with a “soap” lens (under the same conditions), the 300D will have a better (clearer) picture than the 400D (Fig. 9).

Rice. 9. The EF-S 18-55 II kit lens is very soapy on the 400D and does not allow you to fully utilize the potential of the 10 megapixel matrix: detail is not much higher than that of the 6 megapixel 300D, and in some places even worse (the texture is lost due to blur). Shooting parameters: f=18 mm, f/3.5, 1/1000 s, ISO 100, conversion from RAW using Capture One

Note: During the experiment, it was noticed that the 400D at the same shutter speed produced a darker image than the 300D. This may be due to the fact that the actual sensor sensitivity of the 300D is higher than that set on the display (this, for example, was noticed in the 20D and 5D cameras - setting ISO 100 actually corresponds to a sensitivity of ISO 125).

One of the options to “overcome” the soapiness of the lens is to close the aperture by 2-3 stops. In this case, aberrations are reduced and the picture becomes sharper (Fig. 10).

Rice. 10. Stopping down the aperture reduces blur, especially in the corners, and makes the picture sharper: Canon 400D, f=18 mm, ISO 100, converted from RAW using Capture One

Another option is to use more sharp lens. For example, if you put the EF 100 2.8 MACRO USM on the 400D (one of the sharpest Canon lenses), then we get a noticeable increase in detail compared to 300D (Fig. 11).

For more information about testing a lens and assessing sharpness, see the article "How to test a lens before purchasing. Checking a used lens."

6

Diffraction blur - aperture (hole) too small

At a fully open aperture, the lens is most susceptible to aberrations (it lathers more). Therefore, you have to cover the diaphragm. And it would seem that at f/22 we should get the sharpest picture. However, this does not happen! The 400D already has an aperture of f/11 sharpness starts fall because of diffraction effects— the ideal “point” is blurred into a diffraction spot. The size of this spot becomes let's measure with matrix pixel (5.7 µm). From here we draw another conclusion: what smaller pixel topic matrices already range workers aperture For example, for the 400D, the greatest sharpness of the kit lens in the wide-angle position is obtained at the f/5.6 - f/8 aperture.

Theoretically, the “maximum permissible aperture”, from which diffraction blurring begins, can be estimated as follows: d x 2 , Where d— photosensor size, microns. So, for 400D we get 5.7 x 2 = 11.4; for 5D - 8.2 x 2 = 16.4. Generally speaking, the size of the photosensor is not so easy to find out. It can be calculated approximately by dividing the length of the matrix by the number of pixels. However, more reliable information can only be obtained from the manufacturer. So, for example, according to Canon 1D Mark III pixel size ( 7.2 µm at 10 MPx) less than 1D Mark II N (8.2 µm at 8 MPx), and the dimensions of the photosensors are the same. Structurally matrix 1D Mark III has a smaller distance between sensor cells (see Fig. 13).