Bright lenses. What is the aperture ratio of a photographic lens. Which fast lens to choose

If you've been into photography at least a little, if you've bought a new camera or lens, you've most likely heard of the aperture ratio of optics. The fact is that aperture is a very important criterion for any lens. When buying a lens, it is usually the aperture ratio that they turn to Special attention. Almost any salesperson in a store will "play" a naive newbie fast lens. And only because sufficiently fast lenses are more expensive than those whose aperture ratio is not very good. In addition, many people naively believe that aperture can solve all the problems that a photographer has in the process of his work.

That's what we decided to talk about aperture ratio with you in our today's article.

To begin with, let's figure out what all the same it is - aperture. If you explain popularly, as they say, “on the fingers”, then the aperture ratio is the ability of the lens to transmit light. Aperture shows what is the maximum possible amount of light a particular lens transmits to the matrix digital camera or on film. The larger the lens aperture, the more light passes through the lens. Therefore, the greater the lens aperture, the more opportunities to take high-quality photographs in low light conditions, without using additional light sources, such as a flash, as well as a tripod for shooting at slow shutter speeds.

What determines the aperture ratio of a lens? And it depends, first of all, on these parameters:

• Diaphragm
• Focal length
• Optics quality

Today we do not see the point in delving into the theory of physics (if you are still interested, open the textbook). We'll just say that the aperture ratio of a lens is the ratio of the diameter of the aperture's widest opening to the focal length. It is this ratio that is indicated on the frame of lenses by their manufacturers. Most likely, you paid attention to such numbers on your lens: 1: 1.2, 1: 1.4, 1: 1.8 1: 2.8, 1: 5.6 and the like. The larger this ratio, the greater the aperture ratio of the lens. Fast lenses include lenses with this indicator of 1:2.8, 1:1.8, 1:1.4 and more.

For general interest, it can be said that the lens, which is considered the fastest in the world, was made in 1966 for NASA and was used to photograph the dark side of the moon. This lens was called Carl Zeiss Planar 50mm f/0.7. Its aperture was equal to 1: 0.7. This lens was made in only ten copies.

Even a novice photographer, not to mention professionals, probably knows that the fastest lenses are portrait lenses, which have a fixed focal length(for brevity, lenses with a fixed focal length in the language of professionals are usually called fixes). Every photographer who considers himself a master of photography should have such a lens. Such fast fixes have one indisputable advantage. And it is very significant. This advantage lies in the fact that fast fixes are quite affordable at their cost. And, besides, if you compare them with fast zooms - fixes are sometimes even better than them and are able to create a very wonderful picture.

Lenses with good aperture are great for shooting portraits, as they give a fairly shallow depth of field. And this, as you know, is very important for portrait shooting.

What is the best portrait lens for the job? With aperture 1: 1.2, 1: 1.4 or 1: 1.8?

As we said today, beginners in photography usually try to get a faster lens for themselves. And sellers willingly offer them such lenses, because they are very expensive, and this, of course, is very beneficial for the store. But this is where the question arises: is it necessary to overpay for a lens with an f / 1.4 aperture, if in real practice you are unlikely to use it?

The depth of field in the picture depends directly on the aperture of the lens you are shooting with. That's why when shooting at f/1.2, f/1.4, and f/1.8, the plane of focus is quite small. In this case, there is a very high risk that not the entire subject will fall into this plane. Here, for example, as in this picture.

Its author believes that he spoiled this shot. He shot it with a wide open aperture of f / 1.2. And that is why I did not get into focus, and the picture turned out to be blurry. But this picture was taken by him, but already with an aperture of f / 2.8. As you can see, the photo turned out quite well: both the background is blurred and the model's face is shown sharply.

In general, f/1.2 should only be used in the most exceptional cases. For example, in case of a real lack of light for shooting. And even that doesn't always help. It is often easier to simply increase the ISO sensitivity (raise the ISO value). This is especially true if you are working with a full-frame camera. Even when shooting with a 50mm prime lens. at f/2.8, it's easy to miss out on sharpness. And then some details of the photographed object in the picture will be blurry. Therefore, we always recommend in this case to play it safe and shoot in good light at an aperture of at least f / 3.2.

Well, in conclusion of our article, let's briefly summarize what was said in it.

So, fast lenses with a fixed focal length are ideal for shooting portraits. It is for this reason that we strongly recommend that every photographer have such a lens.

When you buy a fast lens, do not succumb to the persuasion of sellers and the declared aperture of 1:1.2 or 1:1.4. You will hardly have to shoot at such an aperture. And if you have to, then very, very rarely. That's why, if you still have a choice between a lens with aperture ratio of 1:1.2, 1:1.4 and 1:1.8 - do not waste your money on buying something that you absolutely do not need. AT practical work a lens with aperture ratio of 1:1.8 is quite enough.

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 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- 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.

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 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.

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.

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 photography of architecture, landscapes, still life and studio work, inexpensive kit lenses and L-series lenses with apertures of 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 for you, but quite often there are shootings in low light, then the presence of a stabilizer allows you to save quite 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.

Surely, if you bought a lens, you have heard such a thing as lens aperture. Most likely, it was the aperture that played a key role when choosing a particular lens, and of course the seller tried to sell you a more expensive lens precisely referring to this mystical parameter - aperture, as if it would solve all your problems;)

First, let's figure out what lens aperture is, and what it is eaten with. If it's simple, then the aperture ratio is throughput lens, i.e. Aperture refers to the maximum amount of light that passes through the lens and hits the sensor of a digital camera. The larger the aperture of the lens - the more light can pass through it, the more opportunities when shooting in poor lighting without using a flash or tripod.

The lens aperture depends on the following parameters:

• diaphragm
• focal length
• optical quality

We will not delve into physics, I will only say that the ratio of the maximum open diameter to the focal length will be your aperture ratio (the so-called geometric aperture ratio of the lens). It is this aperture ratio that optics manufacturers indicate on their lenses, for sure you have seen the following signatures - 1: 1.2, 1: 1.4, 1: 1.8, 1: 2.8, 1: 5.6 and so on. Naturally, the larger this ratio, the greater the aperture ratio of the lens. Therefore, fast lenses are considered those with a ratio of 1:2.8, 1:1.8, 1:1.4 or more.

For the record, the world's fastest lens was made in 1966 for NASA, who used it to capture the dark side of the moon. It is called Carl Zeiss Planar 50mm f/0.7 and its aperture ratio is 1:0.7, only ten such lenses were produced.

Every photographer, whether he is a beginner or a pro, knows that the fastest lenses are portrait lenses with a fixed focal length. And of course, every self-respecting photographer has such a lens in his arsenal. Another plus of fast fixes is that they are relatively inexpensive, for example, when compared with fast zoom lenses, but no less high quality.

Fast lenses are ideal for portrait photography because they give a small aperture, which is very important for .

Which portrait lens should I choose, aperture 1.2, 1.4 or 1.8?

There is the fact that beginners want to buy a faster lens, and of course sellers are happy to sell them this lens, which costs many times more. The only question is whether you need to overpay for the f / 1.4 aperture if you practically do not use it!

Then I took another photo, which is doing well: the face is in focus and the background is blurred, but the aperture was already f / 2.8.

I messed up a lot of frames before I realized that f / 1.2 should only be used if there is not enough light to shoot and then, this does not always help, it's easier to increase, especially if you have . Sometimes, even at 50mm prime with f/2.8 aperture, you can miss and many details will be out of focus, so I always play it safe, especially when photographing models, in good light I use aperture no smaller than f/3.2.

As you can see, the depth of field is quite noticeable.