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Camera aperture. Lens aperture: what is it and what is its use? Why do you need a fast lens?

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

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

Aperture - what is it?

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

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

Another factor that determines the size of the aperture ratio is the maximum opening of the aperture pupil. The wider the hole opens, the more light can pass through it. The geometric aperture of a lens is expressed by relating the diameter of the fully open aperture to its distance to focus. The lower the ratio, the greater the aperture ratio.

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

Benefits of a fast lens:

— the ability to shoot at low ISOs without fear of “digital noise” from the matrix;


— lowering the shutter speed, which allows you to shoot in low light;

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

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

— autofocus is aimed faster, which is important when shooting quickly.

When is a fast lens needed?

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

- to create artistic photographs in the evening and at night - high rate aperture allows you to capture even the minimum illumination of shooting objects;

— for photographing at the shortest shutter speed, which is necessary when photographing wild animals or sporting events, where, due to the high speed of movement of objects, photographs 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 good aperture compensates for this shortcoming.

If the photographer wants to make an artistic portrait, photo of a natural object or other artistic image, shooting must be done with the aperture wide open. At the same time, a minimum depth of field and soft blur of the background are ensured, which allows you to visually highlight one object in the photo, to which all the viewer’s attention will be directed.

Article text updated: 02/13/2019

In a photography lesson for beginner photographers on choosing camera settings, we saw a table showing the dependence of shutter speed, ISO and aperture on each other. In the commentary to it, I explained that high-aperture optics (that is, those that allow you to open the aperture as wide as possible) make it possible to reduce photosensitivity when shooting or significantly reduce exposure time. However, again and again in discussions various nuances photographs on the site, the question arises about the advisability of using expensive high-aperture zoom lenses for beginners. Let's try to dig deeper into this topic today and finally understand it.


For those blog guests who haven’t read the tutorial on camera settings, I advise you to read it first. Let me briefly remind you of the essence: the correct exposure of a photo depends on the settings of light sensitivity (ISO), exposure time (shutter speed) and the diameter of the hole in the lens (aperture). The same exposure value can be obtained by changing one of these three parameters separately. The shutter speed range and ISO values ​​are technical specifications specific camera, the size of the relative aperture is a parameter determined by the design of the lens.

The aperture affects not only the exposure value, but also the degree of blurring of the background in the photograph - the wider it is open, the closer the subject and the farther the background is from it (and also, the longer the focal length), the more the background is blurred. Therefore, the first advantage of a fast lens is the ability to greatly blur those objects that are behind our SVKC (the plot-important compositional center).

Aperture needed for bokeh

High-aperture optics (especially zooms) are expensive. There is a common belief among some photographers that there is no point in paying for it, and you can blur the background simply by using a longer focal length. To a certain extent, this is true. If you open the bokeh simulator (the term means “blurry”, “fuzzy”), the link to which is posted in the lesson with a story about shooting kittens (see above) and play with the settings, you will find that the same DOF (depth of field) can be obtained on the insanely expensive Canon EF 85mm f/1.2L II USM portrait prime and the cheap Canon EF 70-300mm f/4.0-5.6 IS USM telephoto lens. For example, with a distance to the subject of 5 m and an aperture of f/1.2 with a Canon 85mm f/1.2 fix, you can get a depth of field equal to 15 cm. If you screw the above-mentioned Canon 70-300 telephoto onto the camera and move to a distance of 15 m, then when the maximum open aperture f/5.6, we get the same depth of field of 15 cm. However, the portrait will turn out to be large-faced, not half-length...

Shooting wide open can be difficult due to the shallow depth of field when photographing at close range. I encountered this, for example, while photographing kittens (see the lesson on blurring the background at the link above): they are small, you have to get close, there is not enough light in the room, opening the relative hole leads to a decrease in depth of field - only the head is sharp. Therefore, I am ready to partly agree or at least not argue with those amateur photographers who claim that there is no reason for expensive high-aperture optics.

Aperture is needed to shoot at low ISOs with short shutter speeds

On cropped Nikon DSLR D5100 My main standard lens was a fast zoom Nikon 17-55mm f/2.8G. When switching to a full-frame Nikon D610, I bought a Nikon 24-70mm f/2.8G ED AF-S Nikkor full-frame reportage lens for it. In the comments, some photographers noted that it would be better to take the cheaper, but dark Nikon 24-120mm f/4G ED VR AF-S Nikkor zoom, because the difference in aperture is only one stop. In response, I said that even this often gives me a noticeable advantage. Let's see why this is so.

The photographer's task is to shoot at the lowest ISO value so that there is no digital noise that spoils the image.

I took the two shots above with the camera set to . The subject was stationary, so there was no need for a fast shutter speed. Everything changes if we do not have the opportunity to put the camera on a tripod: we must use the formula: B = 1/FR for cameras that have a matrix with a small amount pixels like Nikon D7000 or V=1/(2*FR) for multi-pixel sensors like Nikon D7200.

The situation gets even worse if we photograph moving objects in poor lighting: we need an even shorter exposure time, which means we need to raise the ISO even higher.

For example, in the spring of 2016, my wife and I went on vacation to Turkey. , where I photographed a marble column with the head of Medusa the Gorgon.

While photographing the scene with my fast wide Samyang 14mm f/2.8, I tightened the aperture to f/5.6 because I was afraid that I wouldn’t get into the depth of field. Now I see that this was a mistake: at short focal lengths the depth of field of the imaged space is quite large, and Medusa’s face would have turned out sharp - it was possible to open the aperture to f/2.8. This would give me the opportunity to lower the ISO or shorten the shutter speed to 1/250 of a second, that is, the tourists would come out clear and not blurry (note: although, I believe that blurry people here do not spoil, but rather improve the picture).

As you can see, for a full frame Nikon D610, the photosensitivity of ISO 25’600 is completely unworkable. You can try converting the image to black and white.

Another way is to use noise reduction (noise reduction), but then we lose details: the picture becomes plasticine.

To better understand how an open aperture helps reduce light sensitivity and speed up shutter speed, I suggest once again compiling a table that displays the relationships between these parameters. I take the camera, put it on a tripod and change the settings, writing down the values.

Note. In ISO settings, numbers of the natural range are usually displayed, extended ones are hidden behind abbreviations: L1.0 - 50, L0.7 - 64, L0.3 - 80 for parameters below ISO100, and for numbers above 6400 units - H0.3 - 8' 063, H0.7 – 10'159, H1.0 – 12'800, H2.0 – 25'600 units.

There is no need to memorize the numbers in this table: they change at any given time depending on the lighting of the scene we are shooting. But they can be analyzed. I suggest doing this using the example of the image I received,

If instead of the fast Nikon 35mm f/1.4G I had used my Nikon 24-70mm f/2.8 reportage zoom, then at open f/2.8 the aperture would have differed by 6 stops (f/1.4, f/1.6, f/1.8, f /2.0, f/2.2, f/2.5 and finally f/2.8). It follows from the table that to obtain the same time in an exposure of 1/100 second, ISO would have to be raised from 320 units to 1250. On cropped cameras, this value is the threshold for obtaining high-quality images. Full frame copes with high ISO better: up to 2900 units for Nikon cameras and 2300 for Canon cameras EOS. Therefore, a Nikon 24-70mm f/2.8 zoom would not spoil the picture.

Now, let’s assume that I decided to save money and instead of my expensive fast lens, I took a darker version of the Nikon 24-120 f/4.0. At open f/4.0, the difference with the f/1.4 aperture is 9 steps - ISO needs to be raised from 320 to 2500 units - on the verge! Third option: take the cheapest kit lens for full frame Nikon AF-S Nikkor 24-85 mm F 3.5-4.5G ED VR SWM IF Aspherical. It forces you to set the already non-working ISO 3200.

And the last option is, say, a very dark ultra-long telephoto lens Sigma 150-600mm f/5-6.3 DG OS HSM Sports Lens. The difference with the Nikon 35mm f/1.4G prime is 13 stops, which means to shoot this particular scene at f/6.3 you will need ISO 6400 units!

Such are the metamorphoses. Do you agree that the difference is stunning? But, probably, one of the photographers will say: “So in the open - the depth of field is too small. In practice, you won't be able to open the aperture to the maximum." And here I want to show a photo report that I took during a business trip to Germany on December 10, 2016. In the evening we went to the New Year's fair in Frankfurt - there was no light at all, then we visited the Düsseldorf automobile museum "Classic Remise Düsseldorf" and the famous Cathedral in Cologne, where the lighting was also not so great. I had with me a full-frame Nikon D610 body and only a fast Nikon 24-70mm f/2.8G zoom. This is what came out of all this.

Shooting a report with a fast zoom

So, we came to the fair when it was already dark outside. We are shooting carousels - to make it come out sharp, you need a short shutter speed.

Here, of course, the aunt in the foreground did not hit the depth of field and ruined the frame. But when we are filming a story where the SVCC is in the foreground (and that is the majority), this problem does not arise.

Photo 10. High-aperture optics are not a problem for the photographer in shots where the main subject is in front. 1/1000, +0.67, 2.8, 3200, 56.

To photograph moving objects, we need to install very short shutter speed. Fast lenses allow you to get very short time exposition. It’s not for nothing that such glass is called “fast lens” in English.

Of course, when shooting diverse scenes, you always need to remember about the depth of field and analyze whether all important objects will be included in the zone of sharpness. Either it's flat plots.

Photo 13. Shooting at the open aperture of a fast lens always balances on the edge of depth of field. 1/500, +0.33, 2.8, 3200, 45.

The next photo was taken at f/2.8 at ISO 6400. According to table No. 6, when shooting with a dark travel zoom Nikon 28-300mm f/3.5-5.6G ED VR AF-S Nikkor, at the short end at f/3.5 there will be H0 .7 (ISO 10'159). At long, at f/5.6, we would have set it to H2.0 (ISO 25’600), and this would not have been enough, the picture would have turned out dark, that is, underexposed.

A couple more reportage shots demonstrating the fact that the f/2.8 aperture is not a problem as long as our SVKZ is in the foreground.

However, the advantage of the Nikon 24-70mm f/2.8 light zoom is crucial, if the photographer has the opportunity to shoot from afar. As you approach the subject, the depth of field decreases sharply and, despite the darkness, you have to clamp the aperture.

To get the camera into the cutting zone, I had to reduce the focal length of my lens. But the plot turned out completely different.

Okay, the examples above were mainly written for extremely difficult lighting conditions. Let's look at scenes shot indoors during the day.

Lately I have been actively using the " Automatic control ISO" on its Nikon camera D610. In most cases it works great, but here it failed: I think that for handheld shooting a shutter speed of 1/40 of a second was enough, which means the ISO would have dropped to 400 units.

When it comes to choosing lenses for crop or full frame, two approaches often collide: 1) one universal zoom (high-quality, but expensive) or 2) a set of cheaper primes. I can be considered a fan of zooms - on this excursion I received yet another confirmation of this position: I would not have taken the following photo with a wide shot, showing the viewer the scene of action, if I did not have a Nikon 24-70mm f/2.8 zoom. It was not possible to take fixes with us on a trip.

The next few frames probably cannot be considered a good illustration for this article, since due to failures of the Auto-ISO functions, the shutter speed was too short with an unreasonably high light sensitivity. At least I was convinced that for some scenes ISO 6400 is not critical.

Photo 25. A trip to the automobile museum with high-aperture optics. If I had not trusted the automation, I could have easily lowered the ISO. 1/400, 5.6, 6400, 29.

Photo 27. Large sizes The shooting object does not allow you to take advantage of high-aperture optics - the aperture is tightened due to the small depth of field. 1/640, -1.0, 5.6, 6400, 24.

I want to show two identical photographs taken at different ISOs. Oddly enough, I don't see much difference. Well, maybe the ISO 100 shot is a little better in the shadows.

We continue our journey. We saw the Christmas market in Frankfurt am Main and the Classic Remise Düsseldorf automobile museum. Now let's move to the glorious city of Cologne.

Photo 31. We’re shooting through the car window—it’s clear that we focused not on the car, but on the building in the distance, which ruined the shot. 1/100, -0.67, 5.6, 640, 70.

Of course, Cologne is famous for its Cathedral. , I said that you need to set a goal to visit all the buildings presented there in reality. Apart from the Statue of Liberty in New York, Cologne Cathedral is a close second.

We go inside the Cathedral. I don’t know if you can use a tripod there, but I would like to, since the room is very dark. You have to take photographs handheld, setting the maximum possible shutter speed to shoot without blur. After processing the photo looks pretty good.

According to table No. 6 “Ratio of shutter speed, aperture and ISO,” if I, at one time, had chosen the darker Nikon 24-120 f/4.0 zoom, I would have had to “raise” the ISO to H1.

At an open aperture, my fast glass even allowed me to photograph the stained glass windows of the Cologne Cathedral handheld without losing image quality.

When shooting with a dark Nikon 28-300mm travel zoom, you would have to set the ISO to 2500 units (at f/ 5.6)

I can’t think of anything to comment on the rest of the pictures from the excursion to the Cologne Cathedral, just look at the difference when shooting in a dark room and outdoors.

Across the road from the Cathedral there is a beer garden. It would be a sin not to come here without trying a glass or two of Cologne Kölsch. Another test for my fast Nikon 24-70mm f/2.8 reporter.

Photo 39. Yes, small depth of field is a problem... 1/250, 2.8, 6400, 70.

This is the long way I found to show off my trip in a rented car in Germany. Joke! Seriously, the example images in today's report, in my opinion, show that the full-frame Nikon D610 camera has a working ISO of up to 5600 units, and at 6400 we already get “plasticine”. Well, a fast lens is a good help for taking photographs in low light conditions.

Since my photos are in a New Year’s mood, I’ll take this opportunity to congratulate you, friends. I wish that in your families next year everything was great, your hobby didn’t ruin you family budget(which is difficult to provide, since high-aperture optics cost money), and also made you and your loved ones happy. Happy New Year, my friends!

P.S. I hope this article will help newbies understand how to get great New Year's pictures. There are two ways out here: either run to the store for high-aperture optics, or external flash, which will allow you to get a short shutter speed even with a dark lens.

The time when smartphone camera quality was measured in megapixels is over.

This parameter has been replaced by more important ones: aperture (aperture), focal length, physical size of the matrix, capabilities software cameras and others. Most photographs today are taken with a camera. mobile phone, and when choosing a new gadget, they pay a lot of attention to it. Manufacturers are increasingly focusing on the aperture ratio of the smartphone camera. While specifications increasingly demonstrate lens aperture as an advantage, there is virtually no information about the size of the matrix.

What is a diaphragm?

In specifications, aperture is designated by the letter f, and the smaller the value, the better it is considered. For example, if two smartphones have an aperture of f/1.7 and f/2.2, then, all other things being equal, the first one should make the photo brighter and clearer.

The aperture determines the size of the hole through which light enters the sensor. The smaller this parameter is, the more light will pass through the lens. An equally important parameter is the size of the matrix: if it is minimal, then the aperture will not help you take a high-quality picture in the dark.

Current aperture value

The value of the aperture parameter in the average price segment today is 2. This is enough to take high-quality detailed photos in the twilight or dark room.

Increasing the aperture number leads to a decrease in depth of field. This way you can blur the background in portrait photos, highlighting the subject in the foreground. This effect is called Bokeh and is actively advertised as a feature of modern gadgets.

On smartphones with zoom support, two aperture values ​​are indicated depending on the degree of zoom. The first number characterizes the maximum aperture when shooting with maximum angle, the second indicator indicates the limiting aperture value when shooting with a telephoto lens. As the zoom changes, the aperture level also changes, so two parameter values ​​are indicated.

Modern smartphones have already reached the aperture ratio of mid-budget point-and-shoot cameras, but with an identical aperture number, the size of the matrices differs in favor of the cameras. Despite the development of mobile shooting technologies, they benefit from the size of the matrices and other components.

Material copied with the kind permission of the author.

I think you have often heard words like “ lens aperture".

Let's figure out what it is. Aperture refers to how much light can pass through a photographic lens and hit the camera's sensor. The faster the lens aperture, the more options you have when shooting in low-light situations without using a tripod or flash.

The lens aperture depends on three parameters:

  • focal length
  • diaphragm
  • quality of optics

Maximum open diameter ratio aperture to the focal length is called aperture (geometric aperture of the lens). It is this optical aperture that is indicated on the lenses, I think you’ve seen the signatures - 1:1.4, 1:2.8, 1:5.6, etc.. Of course, the higher the ratio, the greater the lens aperture (the ratio 1:1.4 is greater than the ratio 1:3.5).

The fastest lens, was released for NASA in 1966 and was used for photography dark side moon. It was called Carl Zeiss Planar 50mm f/0.7 and its aperture ratio was 1:0.7, ten of them were made.

A fixed focal length portrait lens is one of the fastest available. Fast primes are relatively cheap, for example when compared to a fast zoom lens.

A fast lens is ideal for portraits, they give a small depth of field what is important for portrait photography.

Which lens to choose, with aperture 1.2, 1.4 or 1.8?

Beginners usually want to buy a faster lens, which costs much more. But do you need to pay for an f/1.4 aperture if you won’t use it!?

Depth of field (abbreviated DOF) depends on how fast the lens is, so when shooting at f/1.2, f/1.4 or f/1.8 the focal plane is quite small and your subject may end up outside the focal plane.

The f/1.2 aperture should be used when there is not enough light, although this does not always solve the problem, it is easier to raise ISO, especially if you have full-length camera. Sometimes, even at 50mm with an aperture of f/2.8, many details may be out of focus, so it’s better to play it safe and use an aperture of at least f/3.2:

So

The fast lens is ideal for portrait photography.

If you have been at least a little involved in photography, if you have bought a new camera or lens, you have most likely heard about the aperture ratio of the optics. The fact is that the aperture ratio is very important criterion any lens. When buying a lens, it is the aperture ratio that people usually pay attention to. special attention. Almost any salesperson in a store will “foist” a fast lens on a naive beginner. And only because fairly fast lenses are more expensive than those whose aperture is not very good. In addition, many naively believe that aperture can solve all the problems that arise for a photographer in the process of his work.

It’s about aperture ratio that we decided to talk to you about in our article today.

First, let's figure out what it is - aperture. If you explain it popularly, as they say, “on your fingers,” then aperture is the ability of the lens to transmit light. Aperture shows the maximum possible amount of light a particular lens transmits to the matrix of a digital camera or to photographic film. The greater the aperture of the lens, the more light passes through the lens. Therefore, the greater the lens aperture, the more opportunities to do high quality photos in low light conditions, without using additional light sources, such as a flash, as well as a tripod for shooting at long exposures.

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

  • Diaphragm
  • Focal length
  • Optics quality

Today we see no point in delving into the theory of physics (if you are still interested in this, open your textbook). We'll just say that lens aperture is the ratio of the diameter of the widest open aperture to the focal length. It is this ratio that their manufacturers indicate on the lens frames. Most likely, you paid attention to the following numbers on your lens: 1: 1.2, 1: 1.4, 1: 1.8 1: 2.8, 1: 5.6 and the like. The greater this ratio, the greater the lens aperture. Fast aperture lenses include lenses with a ratio of 1:2.8, 1:1.8, 1:1.4 and more.

For general interest, the lens, which is considered the fastest in the world, was manufactured 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 ratio was 1:0.7. This lens was produced in only ten copies.

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

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

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

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

The depth of sharp space in the image depends directly on the aperture of the lens you are shooting with. This is why when shooting with apertures of 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. For example, like in this picture.

Its author believes that he ruined this shot. He shot it with a fully open aperture of f/1.2. And that’s why it didn’t come into focus, and the picture turned out blurry. But this picture was taken by him, but 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 sharp.

In general, the f/1.2 aperture should only be used in the most exceptional cases. For example, in case of a real lack of light for shooting. And even then this does not always help. Often it is easier to simply increase light sensitivity (raise the ISO value). This is especially true if you are working with a full-format camera. Even when shooting with a fixed focal length lens of 50mm. With an aperture of f/2.8, it's easy to fall out of focus. 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 lighting at an aperture of no less than f/3.2.

Well, at the end of our article, let’s briefly summarize what was said in it.

So, fast prime lenses are ideal for portraits. It is for this reason that we strongly recommend every photographer to have such a lens.

When you buy a fast lens, do not be fooled by sellers and the stated aperture ratio of 1:1.2 or 1:1.4. You are unlikely to shoot at such an aperture. And if you have to, it will be very, very in rare cases. That's why, if you still have a choice between a lens with an aperture of 1:1.2, 1:1.4 and 1:1.8, don't waste your money on buying something you don't need at all. IN practical work A lens with an aperture ratio of 1:1.8 is quite sufficient.