The higher the luminosity, the. How to choose a smartphone with the best camera

In everyday life, many photographers under the words 'Aperture', 'Aperture', 'Relative aperture' often mean the same thing.

If everything is greatly simplified, then the number F (aperture number) is only responsible for the ratio of the geometric aperture of the lens to its focal length - therefore, you can also find the definition that the number F is called geometric aperture . In fact, aperture is the ability of a lens to transmit light, and this ability is affected not only by the ratio of the focal length of the lens to its diameter (i.e., geometric indicators). A huge role in the possibility of light transmission is played by the optical scheme of the lens, which tends to transmit not all the incident light.

An ideal lens would transmit all the light that falls on it, but due to reflection, re-reflection and absorption by the optical elements of a real lens, only part of the light flux reaches the photosensitive element, which forms the final image. Therefore, different lenses with different optical schemes, but with the same relative aperture, can create different exposures in photographs, other things being equal. This is very often encountered in the cinema, where you need to mount a lot of short clips, for example, shot from different angles, into one big one. At the same time, if the scene is shot from different angles with different optics with the same F value, then in the final fusion you can get different brightnesses, which will look very bad when viewed. This is the most primitive example often given by videographers.

To make it more convenient to work with photo and video equipment, there is a so-called T number (from the English 'Transmission' - transmission, transmission). The T-number is an F-number adjusted for the light transmission efficiency of the lens. The T-number indicates the equivalent of a lens with a certain F-number that would let in all 100% of the light. For example, if a 50mm, F/1.4 lens only transmits 50% of the light, then it would be a perfect lens with a T number of 2.0. The number T can be used in the same way as the number F.

Example. If we have a 100mm T 4.0 lens, then no matter what its actual geometric aperture and what F-number it has, it will still transmit as much light as any other lens with the same T-number, for example, some 50mm T4.0. At the same time, 100mm T 4.0 and 50m T 4.0 can have completely different F-number values. If you put a neutral light filter on such lenses, then we can say that their F-number values ​​will be preserved, and the T-numbers will change to a filter dimming step. Thus, T-stop (an analogue of the F number stage) is in many ways more convenient to use.

On the net, I met information that photographers are being deceived by indicating not the real aperture value on the lens barrel. In fact, no one is deceiving anyone, it’s just that there are certain differences between the concepts of “aperture” and “relative aperture”, which an experienced photographer knows about. On the lens, the usual value of the relative aperture is indicated (it is also called the maximum aperture, or F number), but how much light such a lens actually transmits can sometimes only be found in the instructions for the lens.

When I was writing the text for this article, I found an instruction manual for a modern lens, re-read it from cover to cover, but did not find information about the light transmission of the lens. Therefore, the manufacturer can still be slandered for incomplete information about lenses.

Due to the different light transmission coefficient, even small paradoxes with the f-number F can occur. For example, let's take two lenses - (lens for cropped cameras) and (full-format lens). It would seem that the first lens has a slightly larger aperture than the second. But if you try to shoot with these lenses using a cropped camera, it may turn out that the amount of light projected onto the camera matrix by the first lens will be less than the second. This is due to the fact that the cropped lens has stronger vignetting at F / 1.8 and with different losses of light flux in optical schemes.

Many aspiring photographers tend to use fast optics for generally accepted reasons - reduced DOF, more flexible DOF control, beautiful pattern, and excellent image quality. But fast optics gives some more very pleasant (or maybe not pleasant?) nuances.

The first of them I want to note the brightness of the optical viewfinder. High-aperture optics give a nice bright picture in . With such lenses, it is much more convenient to aim manually, you do not need to peer hard into and squint your right eye. The human eye adjusts very well to the intensity of lighting, and therefore the difference with different lenses is not always noticeable, but it is. Personally, I tried to determine my personal sense of brightness with a fast lens with manual iris control - . Here's what I noticed:

• The difference between F / 1.2 and F / 1.4 is not felt at all
• The difference between F / 1.4 and F / 2.0 is almost imperceptible
• The difference between F / 2.0 and F / 2.8 can already be easily caught, but on F / 2.8 everything is clearly visible and does not cause any discomfort
• The difference between F / 2.8 and F / 4.0 is simply colossal, you immediately notice it. Visually, working at F / 2.8 is much more pleasant
• The difference between F / 4 and F / 5.6 is not very noticeable, but on F / 5.6 after F / 2.0 there is a feeling of severe limitation.
• When you close the aperture further, everything becomes faded.

Based on my experience (and some others), I have come to the conclusion that F / 2.8 and below are the most comfortable values ​​\u200b\u200bof the maximum relative aperture for sighting.

You can conduct your own experiment on the brightness of your camera. This is easiest to do if the camera is via . If there is no such function, then you need to use a lens with manual iris control. The electronic viewfinder is not suitable for this test.

Bokeh Helios-44 with 8 petals. Photo separator

High-aperture optics not only gives a brighter and brighter picture in, but also allows, in many cases, the auto focus system to cope much more accurately and faster .

Roughly speaking, the stronger the light flux from the lens to the mirror, the easier it is for the phase focus sensors to focus. The first time I felt the difference was shooting in the studio for a long time, where I had a weak modeling light from the illuminators at hand. The fast lens that I used for the waist portrait easily clung to the subject, but when I had to shoot a group of people and use the standard zoom with medium aperture, it simply refused to focus in such lighting.

I suppose that fast optics should improve the quality of focusing also in Live View mode.

In addition to improvements in the focusing system, the camera, with fast lenses in certain conditions, also measures much more accurately. I can’t say exactly how much and for what reasons this or that camera improves the performance of the exposure meter, but, based on my experience, for some reason I’m sure that there are much fewer errors with fast optics.

In my practice, errors in most often occur when using medium aperture optics and when shooting on covered apertures. When using high-aperture optics at the same values ​​of the F number, the errors are much less. Of course, small errors are not critical if you shoot in RAW, but still this is a good plus for such lenses.

Also, I notice that fast optics give less rejection due to focusing errors when used on covered apertures. I assume that if a slight error was made when focusing on a fast lens, then during shooting when the aperture is closed, a noticeable expansion simply compensates for this error.

For those who don't know, modern SLR cameras always focus at full aperture and close it to the set value only when the shutter is released.

For example, let's take a fast fifty dollars with F / 1.4 and a regular regular zoom with F / 3.5-5.6. We will shoot at 50mm and f / 6.3. If the error of focusing on fifty dollars was initially made, then due to closing the aperture to F / 6.3, the depth of field zone will greatly expand and most likely capture our subject. At the same time, if there was a focus error at the zoom, then a slight change in depth of field when moving from F / 5.6 to F / 6.3 will not be able to compensate for inaccurate focusing.

True, fast-aperture optics have obvious drawbacks. One of them I want to highlight the diffraction threshold, which sometimes starts with F / 8. Super-aperture lenses with F / 1.4 and F / 1.2 and below suffer especially from diffraction at tightly closed apertures. Usually the minimum number of F they can use is F/16. Non-aperture optics are less prone to diffraction because it needs to perform a smaller aperture maneuver. So regular "dark" zooms at F / 8 only come to life and show excellent photo quality. This can be critical only for certain types of shooting, and different lenses have different thresholds. The features and subtleties described by me cannot always be clearly shown, but over time they begin to be felt in practice and affect the work :)

↓↓↓ like :) ↓↓↓ Thank you for your attention. Arkady Shapoval.

Fast lenses for nikon and canon: what is lens aperture and f number?

Any lens is characterized by one or another aperture. This parameter is understood as the degree of attenuation by the lens of the light flux entering it. The aperture ratio is affected by the transparency of the lenses, the aperture diameter and some other characteristics of the optics. But if you come to an electronics store and ask the seller about the aperture ratio of a particular lens, you will get a strange answer. A person will simply tell you the maximum aperture value. The fact is that in our age of widespread simplification, people begin to mean precisely the size of the aperture by aperture. This lesson will tell you just about the diaphragm. We will try to explain why this parameter needs to be adjusted when shooting and what it affects.

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. After all, f stands for 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 a fast lens is bought separately. As a result, a slightly larger amount is spent in 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, a lot of them have also been created, 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, more than 24 thousand rubles are asked for glass in Russian stores. Full-frame DSLR owners should be interested in the Nikon 24-70mm f2.8G ED AF-S Nikkor lens. 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.

What is written on the lens?

Please look at this lens - what do the numbers on the lens barrel mean?

Aperture of a lens is the aperture value of a lens when it is fully open.

For the lens in the photo just above, the lens aperture is 2.6. And the smaller the number, the greater the aperture ratio of the lens . Paradox?

There is no paradox here ... when we say MAXIMUM DIAPHRAGM, it means that it is completely open and we mean the size of the aperture hole, and not its designation with a number. And the number indicating the aperture at its maximum opening will be minimal because in reality it is the denominator of a natural fraction (if you notice, 1: 2.8 is written on the lens barrel - these two points are a mathematical division sign, often there is so little space on the frame, that the division sign and the unit are simply not written

Why is lens aperture important when choosing a camera?

When choosing a camera with a removable (=interchangeable) lens, you can buy a fast lens and replace the one you already have. But if you are going to buy a camera with a fixed lens (for example, a compact camera), it is very important to find a suitable model of a camera with a fast lens - with an aperture of no worse than 2.8. Because the more the lens aperture opens, the more freedom you will have, the freer you will feel in non-standard lighting conditions.

In addition, the depth of field depends on the aperture of the lens. In turn, depends on your photos.

Many compact cameras have a very limited choice of apertures, and as a result, a large depth of field. Moreover, some super-compact models of digital cameras and almost all cameras do not have smartphones and phones - in such cameras, instead of the classic diaphragm (an adjustable hole in the partition between the lens lenses), a special filter is used, the transparency of which is regulated by the camera electronics. With such a camera, it is generally impossible to influence the depth of field. I'm not going to say it's good or bad. It all depends on

If you don't want to "bother" with the camera settings and you like to just point the camera at the subject and press the shutter button - you won't even notice the difference. If you like to experiment a lot, shooting in different, often not ideal, lighting conditions, 2 or 3 apertures available can severely limit your options.

03.12.2011 13786 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, you need shutter speeds faster than 1/1000 s. 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 lighting 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. In digital cameras, lower sensitivities and faster shutter speeds result in a more noise-free image.

An important factor for artistic photography is that 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 the background, foreground, or unnecessary detail 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.

small depth of field

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 step. 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 the natural size is taken, even by two. Thus, at the initial relative aperture of f / 4, autofocus will not be possible at all.

That's why photographers spend more money and carry heavier lenses when they could use lighter, cheaper zooms with exactly the same focal length range.

If one day you are going to buy a new camera, the consultant will definitely offer you several expensive models, arguing the correct choice of one of them with a good indicator of aperture ratio.

What is this parameter - lens aperture, what does it affect and why is it needed at all?

Aperture - what is it?

As you know, in order to obtain a photographic image, it is necessary that a certain amount of light enters the camera matrix, passing through the lens optics. It is clear that not all of the light flux will pass through the hole. The aperture ratio shows how much the light flux will weaken when passing through the system of optical lenses.

No matter how high-quality glass is, it can never be completely transparent. Therefore, some part of the light waves, when penetrating through it, is scattered, refracted in random directions, the other part is absorbed by the lens body, made of glass or high-transparency optical plastic. This is the main reason for the weakening of the light flux.

Another factor that determines the size of aperture ratio is the parameter of the largest aperture pupil opening. The wider the hole opens, the more light can pass through. The geometric aperture ratio of a lens is expressed by correlating the diameter of the fully open aperture with its distance to the focus. The smaller the ratio, the greater the luminosity.

For example, a lens marked 1:1.8 (or f1.8) is faster than a lens marked 1:2.8 (or f2.8). In this formula, the main indicator is the diameter of a fully open aperture, which is often used as the most simple and visible expression of the aperture ratio of a particular lens.

Benefits provided by a fast lens:

- the ability to shoot at low ISO, without fear of the "digital noise" of the matrix;


- lower shutter speed, which allows you to shoot with a lack of light;

- when shooting with a reflex camera, the viewfinder becomes brighter and more convenient for choosing the angle;

- the depth of field is limited, the subject is visually separated from the background;

- Autofocus is faster, which is important when shooting fast.

When is a fast lens needed?

As a rule, for ordinary everyday shooting of personal events, the aperture parameter is not too important. Professional photographers use fast lenses:

- to create artistic photographs in the evening and at night - a high aperture ratio allows you to capture even the minimum illumination of the objects being photographed;

- for photographing at the shortest shutter speed, which is necessary when shooting wild animals or sporting events, where due to the high speed of the movement of objects, photos often come out blurry;

- for shooting in poorly lit rooms of nightclubs, fashion shows, dance competitions and some sports;

- in the case when the camera matrix does not have high sensitivity, and a good aperture compensates for this disadvantage.

If the photographer wants to take an artistic portrait, a photo of a natural object, or another artistic image, the shooting must be done with the aperture as wide as possible. This ensures a minimum depth of field and soft blurring of the background, which allows you to visually highlight one object in the photo, to which all the attention of the viewer will be directed.