You need a bright lens. Lens aperture: what is it and what is its use? The effect of aperture on shutter speed

Lens aperture - f number

If you regularly read our lessons, you already know how the maximum aperture value is indicated in the characteristics. So the aperture ratio of the lens is the f number, and to be precise, then f divided by one or another number. Because f means focal length. And the aperture value is the number by which the set focal length is divided.

Aperture must be indicated in the characteristics of any lens. This does not necessarily mean separately sold optics. These words apply even to compact cameras with a built-in lens. Moreover, now the parameter "Aperture" or "Aperture" can be found even in the characteristics of flagship smartphones. Indeed, in the production of cameras built into them, more and more advanced lenses are used. As a result, the device receives high-aperture optics, and the pictures become very bright.

But enough words about the creation of optics. Let's approach lens aperture from the other side. Now we need to understand why buyers pay attention to this parameter at all. And everything turns out to be very simple. If the diaphragm is able to open very wide, then a lot of light enters the matrix. Some lenses provide f/1.4 aperture. With this parameter, you can use a shutter speed of 1/4000 second, while the matrix will have enough light.
Increased aperture favorably affects the quality of portrait photographs. The more the aperture opens, the smaller the zone of sharpness becomes. As a result, you can achieve a beautifully blurred background. This effect is also called the word "bokeh". That is why experienced photographers use fast lenses to shoot portraits. They leave all kinds of zoom optics for shooting landscapes.

Also, glasses with a good f-number are needed for evening photography. In low light, either a slow shutter speed or a wide aperture is required. Nobody will interfere with increasing the shutter speed, but this will not allow you to capture moving objects in the frame. Therefore, it is better to open the aperture to f / 1.8 or f / 1.4. But this method does not always work either. Indeed, with this value, the field of sharpness narrows, and sometimes this does not correspond to the photographer's idea.
Fast lens for Canon and Nikon

In stores, cameras with whale optics are sold in large quantities. And a rare buyer understands that the manufacturer puts a lens with an average, and sometimes even terrible aperture ratio, into the kit. This is especially true for optics with a wide range of focal lengths. Therefore, in various forums and specialized resources, people are recommended to purchase a “carcass”. This word refers to a kit in which there is only a camera. Well, then it is bought separately fast lens. As a result, a slightly larger amount is spent this way than for a kit with whale optics, but the result will please you much more.

Unfortunately, not every lens sold in the store is fast. Be sure to look in the specifications for the aperture value. At 50mm focal length, f/1.8 aperture will be considered fast. The higher the focal length, the smaller the maximum aperture opening. Think of the lenses used by photographers working at football matches. They would give anything for f/2. But it is still technically impossible to achieve it.
Let's take a look at some good fast lenses that you can find in stores these days. At the same time, we are now interested in inexpensive optics for cameras from the two most famous manufacturers - Canon and Nikon.

Let's start with fast lenses for Canon, and here the Canon EF 50mm f1.8 II glass is very popular now. This is the second generation of this optics. As the name implies, the lens has a fixed 50mm focal length. This can be confusing for beginner photographers. But on the other hand, the aperture is able to open up to f / 1.8. Alas, the lens is not the best. Many buyers find fault with its body. But this should not be surprising, since nothing else can be expected from budget glass (you can buy it for 4,000 rubles).

More than four times more expensive is the Canon EF 50mm f1.4 USM. Sometimes even experienced professionals acquire such a lens. They note a very high aperture and beautiful bokeh obtained in the pictures.

If we talk about fast lenses for Nikon, there are also a lot of them, and mostly specimens with a fixed focal length have a high aperture value. For 5 thousand rubles, it is proposed to buy a Nikon 50mm f1.8D AF Nikkor.

This optic delivers the popular 50mm focal length. It is great for cameras with a crop factor of 1.5. But there are also problems with the body, the lens is extremely flimsy.

Nikon 24-85mm f2.8-4D IF AF Zoom-Nikkor looks like a very interesting solution. This is a zoom lens. At the minimum zoom, the aperture can open up to an acceptable f / 2.8 value. But as the focal length increases, the aperture deteriorates. This is the problem with any inexpensive zoom lens. Although this decision cannot be called a budget one, they ask for glass in Russian stores more than 24 thousand rubles.

Full-frame DSLR owners should be interested Nikon lens 24-70mm f2.8G ED AF-S Nikkor. This optic is similar to the previous one, only the range of focal lengths is slightly narrower. But the aperture here does not change when using the zoom! There are other improvements as well. But this lens costs a lot - 65 thousand rubles.
Results: lens aperture - what is it?

It's time to sum up our lesson: lens aperture - what is it and how to understand it correctly? If you are interested in the correct answer, then this is the degree of attenuation of the light flux passing through the lens. But most often the word "aperture" means the amount of aperture opening.

High aperture is needed to get bright photos with high speed exposure. Also, a wide-open aperture is needed to maximize the blurring of the background, which makes for beautiful portraits. Lenses with a fixed focal length have good aperture. If you are interested in fast optics with the ability to zoom, then get ready to spend a lot of money. And the larger the zoom is of interest, the larger the amount required. This is due to the complexity of manufacturing such lenses.

This concludes our lessons on the diaphragm. Visit our site regularly, then you will not miss the following lessons. In them, we will look at the camera in all details and find out which characteristics are the most important.

Lens aperture, what is it? This is the ability to pass light through itself, the more light it passes through, the brighter the image will turn out, the more light it will have. There is a concept of geometric aperture, we omit formulas and calculations, we only note that the ratio of the diameter of the maximum open aperture of the lens to the focal length is the aperture.

Manufacturers mark the received figures on their devices. It looks like this: f / 3.5-5.6, here the aperture ratio is variable. There are models with a constant value, in which the focal length is also constant.

Values ​​for each lens range from 0.7 to 16 (based on known worlds), where 0.7 is the world's fastest lens, a limited edition made specifically for NASA's dark side of the moon. At the same time, in the indicated line, the next value will reduce or increase the amount of light that will pass through 2 times.

Whale optics for the most part has a value of 3.5-5.6, which also affects its inexpensive cost. The higher the value, respectively, the more expensive the optics. The most high price y with a large variable focal length, since technically they are the most complex.

However, buying a particularly fast aperture with a value of 1.2 does not make any sense without proper necessity, especially if you mainly shoot outdoors in good light, you will rarely use this option and spend money completely pointlessly. Aperture makes it possible to obtain high-quality images in low light conditions.

What is a fast lens for?

If you're shooting outdoors in good daylight, or in a well-lit studio, and widening your aperture to f/1.2 or 1.4, there's a good chance you'll ruin your shot. In this case, the subject you are shooting will not be in focus, and the image will lose a lot of depth of field.

Once again, we recall that the maximum aperture should be opened only in order to capture more light, which is not enough. As a rule, in the studio, and even more so when shooting in daylight, it is more than enough.

When choosing for yourself, think about the tasks that you set for him. For a beginner, and sometimes for more advanced ones, the main thing is not to fall into the trap of the "hamster" principle, when both of them can be done without bread.

Well, you won’t be able to buy optics that simultaneously meets all your Wishlist! So that both long-focus, and wide-angle, and the portrait lens are excellent at once, and so that macro- and micro-in excellent quality, and aperture of all spectra, and please, inexpensive. This does not happen, it is necessary to determine and set specific tasks.

For portrait shooting, the option with a fixed focal length and aperture is perfect, some fifty dollars for these purposes is the very thing. For shooting outdoors, beautiful and complex landscapes, sports the best assistant will be a long telephoto lens.

They come with different values, it is worth choosing the one that meets your requirements, and this is not necessarily with a value of 1.2, because in daylight, using the aperture in the open position, I repeat, you will simply ruin the frame.

Having figured out for yourself what lens aperture you need, what it is and how to effectively use the capabilities of your existing lens, you can go for a new, more powerful one, or maybe vice versa. The main thing to remember is what you need to get the highest quality pictures.

Where is it used in optics?

I hope it became clearer to you how lens aperture is used, what is it? Now we can talk about where in general it is used in optics and for what purpose. Now you can easily answer this question yourself.

All lenses used by mankind have their own aperture, whether professional or amateur cameras, or home telescopes, as well as . In telescopes for independent observations of celestial bodies, the luminosity is not so important.

But for filming in space, it has great importance, as in a camera, the quality of the image will depend on how much light the space traveler's optical system will take in.

I thought I'd write the rest in about a month. But no matter how many times I started, I just couldn’t calmly sit down and continue the topic. Now there is some time to put the characteristics of optics, as they say, on the shelves, and the second part is in front of you. Let me remind you that in the previous article we talked about the focal length and its recalculation, taking into account the crop. Today we will consider in detail the aperture ratio and its derivatives - shutter speed and depth of field.

Aperture

After you have decided on the required focal length, aperture is the second most important lens parameter. What will she influence? First of all, for shutter speed - the higher the aperture, the lower the shutter speed, which means you can shoot in darker conditions without a tripod. The second is the blurring of the background, other things being equal, the higher the aperture ratio, the smaller the depth of field and the more the background is blurred. I dwelled on this issue in detail in the article ““, so I won’t especially repeat myself here, but I’ll tell you in a nutshell.

The aperture of a lens is essentially determined by how wide the aperture is opened. Labels such as Canon EF 50mm f/1.4 USM list the maximum aperture as f/1.4. With rare exceptions, Canon has a lens with an aperture of 1.2 and seems to have been preparing with a value of 1, all other lenses have a “narrower” aperture, such as 3.5 or 4 or even 5.6. The maximum values ​​can be constant for high-quality optics (one number is indicated) or variable depending on the focal length for optics of a class below (numbers are indicated with a hyphen). Aperture 2.2 was used for the photo on the left, even for many professional lenses L series, this level of blur is not available.

The effect of aperture on shutter speed

I think now there should be no problems with determining the aperture value, so let's talk about why we need it in real conditions, and not in theory. A small aperture makes the lens lighter or faster, whichever you prefer, compared to a larger one. In other words, a lens with aperture of 2.8 is better for working at dusk or for shooting a dynamic football match than optics with aperture of 4. A slower shutter speed in the first case will allow you to get clear, bright handheld shots, because. with a wider aperture, more light will enter the matrix in the same time. And in the second, it will stop the moment of the game, because. the shutter speed will be very small and the camera will catch the fastest movement without blurring the players.

I'll use the photo above as an illustration. The shooting parameters were as follows - shutter speed 1/1000s, aperture 4.0. These values ​​made it possible to obtain a clear photo of the athlete, although the speed upon landing was quite noticeable. But if it were darker, then the shutter speed would increase and the figure of the jumper would turn out to be smeared, and this is where faster optics would come in handy.

Lens aperture and background blur

I hope this is clear, now the second aspect is blurring the background. In short, if you want a beautiful background blur, take a fast lens. For shooting architecture, landscapes, still life and studio work, inexpensive kit lenses and L-series lenses with f-4.0 are quite suitable. In these genres, all objects in the frame should have sharpness, and blurring the background rather interferes. But if you want to shoot portraits, then separating the model from the background becomes a very important task, and this is where wide aperture optics come to the rescue, because the wider the aperture is open, the more the background is blurred. Also, a shallow depth of field can be useful in macro photography.

For example, let's look at a photo of a lizard. The aperture value is 2.8, the background is blurred and the viewer's attention is focused on the reptile. Already at aperture 4.0, the blur is much less, which will make the photo flatter and distract from the main subject.

Optical stabilizer

Lenses for Canon cameras and Nikon may be equipped with an image stabilizer. Referred to as IS for Canon and VR for Nikon. You can read more about why you need a stabilizer in my other one in the “exposure” section. Sony has a stabilizer built into the camera itself and, accordingly, choosing a lens is somewhat easier.

This digression appeared in an article about aperture ratio for a reason. If blurring the background is not important to you, but quite often there are shootings in low light, then the presence of a stabilizer allows you to save a lot on buying a lens. You can take a less fast lens, but with a stabilizer, while the shutter speeds at which you will get blurry photos will remain approximately the same. In addition, lenses with a smaller aperture are usually simpler in design, which can significantly reduce their weight, and this can sometimes be a big advantage.

To sum up the article, I will formulate brief conclusion by lens aperture. The higher the lens aperture, the wider the range possible conditions lighting and even more beautiful blurring of the background can be obtained, the flip side of the coin is, of course, the price, which grows along with aperture.

03.12.2011 14737 reference Information 0

Lens aperture - a value that characterizes the degree of attenuation of the light flux by the lens. To understand what a fast lens is, let's understand how the lens affects the flow of light.

As you know, when photographing, light hits the matrix, forming an image. The lens attenuates the light output. This degree of attenuation is called aperture ratio.

In simple terms, aperture ratio is the maximum amount of light that a lens can capture. Lens aperture refers to the maximum aperture (hole through which light enters the sensor). It is characterized by a minimum f-number. That is, the smaller the number, the more the aperture is open and more light enters. The minimum aperture value corresponds to the declared aperture. So, at f / 2 aperture, the aperture value can be from two or more.

If the lens is not a fixed lens (with a fixed focal length), then two pairs of numerical characteristics will be indicated on it: the first pair is the minimum and maximum possible focal lengths, the second is the variable aperture corresponding to these focal lengths (the first number is for the minimum, the second is for maximum). There are also more expensive lenses - having a fixed aperture with a variable focal length.

Why do photographers chase fast lenses?

There are many reasons. In a reflex camera, sighting is carried out through a shooting lens - and with relative apertures of 1 / 5.6-8, the human eye already poorly captures the picture, that is, a fast lens is more comfortable for the photographer.

A fast lens can shoot at faster shutter speeds, which is vital when shooting sports and wildlife, because to stop the movement of the wings of a bird, shutter speeds shorter than 1/1000 s are needed. The longer the lens is, the more it needs short shutter speeds when shooting handheld, otherwise it is easy to “blur” the image.

A fast lens can shoot in more challenging light conditions, so indoor fashion, dance, and some sports photographers invest in very expensive telephoto lenses with apertures of f/2.8 and f/2 or more.

A fast lens can shoot at low sensitivity. AT digital cameras lower sensitivities and faster shutter speeds result in a more noise-free image.

An important factor for artistic photography- By changing the aperture value, you can change the depth of field. At full aperture, at apertures greater than f/2.8, the depth of field (DOF) is shallow, allowing backgrounds, foregrounds, or unwanted details to be blurred. This quality is difficult to replace in portrait photography, and in general it is essential for almost any genre, except, perhaps, landscape. The portrait, by the way, does not like too bright light.

IPIG change

For professional-level telephoto lenses, aperture is also important because they are used as part of a photo system with converters that increase the focal length. For example, a 300mm professional telephoto with a one and a half converter turns into a 450mm, and with a double converter it turns into a 600mm.

The luminosity also has one technical limitation. Autofocus systems work reliably at apertures up to f/5.6. At smaller ones - (f / 6.3, f / 6.8 - they usually work, but unreliably and less accurately, and at f / 8 or f / 11 they don’t work at all. But as the focal length increases to the root, the square of two aperture drops by one stop. Accordingly, a telephoto lens with f / 4 aperture and a 2x converter will not work in autofocus mode, since the resulting aperture will be about f / 8, and the viewfinder will be visually darkened.

At the same time, the aperture also changes when focusing. For example, if the lens is focused on an object on a scale of half its natural size (1: 2), then its aperture ratio drops by one step, and if a natural size is taken, even by two. Thus, at the initial relative aperture of f / 4, autofocus will not be possible at all.

This is why photographers spend more money and wear heavier lenses, although they could use light and inexpensive zooms with exactly the same range of focal lengths.

Everyone wants to get beautiful bright pictures when they take pictures. However, very often it turns out that when you see an interesting moment, you manage to capture it, but the photo turns out to be somehow dark. A lens with a low aperture may be to blame for this. That's why it's so important to know what it means. Let's figure it out.

The aperture ratio of the lens is another very significant parameter. It is just as important as the angle of view and others. This parameter characterizes the brightness of the image built on the lens matrix. The faster the lens, the brighter the image it creates. And with a smaller indicator, it will be darker.

Aperture is characterized by the relative value of the size of the hole, and is indicated in the form of a fraction. For example, the inscription ¼ means that for a lens with a relative aperture size of ¼, the aperture diameter is four times smaller than the focal length parameter. It is important to note that the size of the actual objective aperture is rather a virtual value. This diameter usually does not match either the diameter of the diaphragm or the front

It is quite possible to calculate the size of the actual objective hole, but it cannot be measured. Traditionally, relative values ​​are dependent on the size of the image field for which the device is designed. It can be said that lenses with a fixed focal length have a very high aperture, for example, f / 1.4-f / 1.8, unlike those in which the focal length is variable. Usually, for optics with a variable focal length, the aperture parameter is also variable, since their design is much simpler.

If we talk about this, based on some example, then we can say that if the optics are marked 20-80 / 3.4-4.7, this will mean that with a focal length of 20 millimeters, the relative size of the hole will be f / 3.4, and if the focal length becomes 80 mm, then the aperture will change and become f / 4.7. However, the higher the lens aperture, the more expensive the device itself.

It would be ideal to have in your arsenal a set with a different indicator of this parameter, however, for ordinary people this option is not suitable, since spending on them is incommensurable with anything. It makes sense to acquire such expensive equipment only if the photos will be printed in magazines or somewhere else, otherwise not.

In the absence of such a goal, it is quite enough to purchase an ordinary camera. You should not take cameras with a low aperture ratio, since very soon you yourself will feel that the photos are not beautiful and bright enough, and this defect cannot be removed. However, modern devices, even the simplest ones, have very high-quality built-in automation.

At its core, lens aperture is a property that shows the amount of light passing through this device. Based on this situation, lenses that allow only a small aperture have the smallest aperture. Lenses can be slow or fast, that is, having a larger or smaller aperture, depending on the size of the aperture, usually different cameras are compared using it, whose focal length is the same.

According to such a parameter as the aperture ratio of the lens, most often they compare different types photographic equipment. It is believed that at the maximum value of this indicator, the best pictures are obtained in various degrees of illumination. If used, then you have the opportunity not only to change the focal length, but also to get a different aperture ratio.