Which lens aperture is best? About fast lenses

Surely, if you bought a lens, you have heard the concept more than once: lens aperture. Most likely, it was the aperture that played the 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 used with. To put it simply, aperture is the throughput of the lens, i.e. The aperture ratio shows the maximum possible amount of light passing through the lens and hitting the matrix of a digital camera. The larger the aperture of the lens, the more light can pass through it, the greater the possibilities when shooting in poor lighting without using a flash or tripod.

Lens aperture depends on the following parameters:

• diaphragm
• focal length
• quality of optics

We won’t delve into physics, I’ll just 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 that optical manufacturers indicate on their lenses; you have probably seen the following signatures - 1:1.2, 1:1.4, 1:1.8, 1:2.8, 1:5.6 and so on. Naturally, the greater this ratio, the greater the lens aperture. Therefore, fast lenses are considered to be those with a ratio of 1:2.8, 1:1.8, 1:1.4 or more.

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

Every photographer, whether a beginner or a professional, 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 advantage of fast primes 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 provide low aperture, which is very important for.

Which portrait lens to choose, with 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 several times more. The only question is whether you need to overpay for an f/1.4 aperture if you practically never use it!

?

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

I messed up a lot of shots before I realized that f/1.2 should only be used if there is not enough light to shoot, and then this doesn’t always help, it’s easier to increase it, especially if you have . Sometimes, even with a 50mm prime with an 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 lighting, I use an aperture no less than f/3.2.

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

Conclusion

The fast lens is ideal for portrait photography, so any self-respecting photographer should definitely have one in their arsenal.

When buying a fast lens, do not buy the stated 1:1.2 or 1:1.4. You will rarely use the widest aperture, so if you have a choice between a fast portrait lens 1:1.2, 1:1.4 and 1:1.8, don’t make the mistake and don’t spend extra money buying the fastest available lens, a portrait lens with aperture ratio 1:1.8.

Thanks for reading and see you next time.

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 a certain amount of light enters the camera matrix, 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 light 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 personal life events, the aperture parameter is not very important. Professional photographers use fast lenses:

- for creating artistic photographs in the evening and at night - the high aperture ratio allows you to capture even the minimum illumination of the subjects;

— 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 a good aperture compensates for this disadvantage.

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

Lens aperture - f number

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

The 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 “Aperture” or “Aperture” parameter can be found even in the characteristics of flagship smartphones. After all, more and more advanced lenses are used in the production of cameras built into them. 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 generally pay attention to this parameter. And everything turns out to be very simple. If the aperture can open very wide, then a lot of light enters the matrix. Some lenses offer an f/1.4 aperture. With this parameter, you can use a shutter speed of 1/4000 of a second, and there will be enough light for the matrix.
Increased aperture has a beneficial effect on the quality of portrait photographs. The more the aperture opens, the smaller the sharpness zone becomes. The result is a beautifully blurred background. This effect is also called “bokeh”. This is why experienced photographers use fast lenses to shoot portraits. They reserve all zoom optics for landscape photography.

Also, glasses with a good f-number are needed for evening photography. When there is insufficient lighting, either a long shutter speed or a wide open aperture is required. There is no harm in 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. After all, with this value the zone of sharpness narrows, and sometimes this does not correspond to the photographer’s intention.
Fast lens for Canon and Nikon

Cameras with whale optics are sold in large quantities in stores. And it’s rare that a buyer understands that the manufacturer includes a lens with an average, and sometimes even terrible, aperture in the kit. This is especially true for optics with a wide range of focal lengths. Therefore, on various forums and specialized resources, people are recommended to purchase a “carcass”. This word refers to a kit that only contains a camera. Well, then you buy a fast lens separately. As a result, you spend a little more money than for a kit with kit optics, but the result will please you much more.

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

Let's start with fast lenses for Canon, and here Canon EF 50mm f1.8 II glass is very popular now. This is already the second generation of this optics. As the name suggests, the lens has a fixed 50mm focal length. This can be confusing for new photographers. But the aperture can 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 it is impossible to expect anything else from budget glass (it can be bought for 4,000 rubles).

The Canon EF 50mm f1.4 USM costs more than four times more. Sometimes even experienced professionals purchase such a lens. They note the very high aperture ratio and beautiful bokeh obtained in the photographs.

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

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

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

Owners of full-frame DSLRs 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 size of the aperture opening.

A high aperture ratio is needed to obtain bright photographs at high speed shutter speeds. Also, a wide open aperture is necessary for maximum background blur, which results in beautiful portraits. Fixed focal length lenses have good aperture. If you are interested in high-aperture optics with zoom capabilities, then get ready to spend a lot of money. And the larger the zoom you are interested in, the larger the amount required. This is due to the difficulties of manufacturing such lenses.

This concludes our lessons on aperture. Visit our website regularly so you won't miss the next lessons. In them we will look at the camera in detail and find out which characteristics are the most important.

The aperture of a lens is its ability to transmit light. Some light is always lost when passing through the lens. The more light passes through, the greater the aperture of the lens.

Take a rectangular sheet of paper and roll it into a tube, first along and then across. With the same hole diameter, you will get different tube lengths. A shorter tube will be brighter (more lens aperture) than a long tube (less lens aperture), because the light has less distance to travel from end to end and will not be attenuated by reflections inside the tube. Therefore, the relative opening is calculated as the ratio of the length of the tube to the diameter. This means that in order for a long tube to be as bright as a short one, it is necessary to increase its diameter so that more light passes through.

It is not necessary to know the exact formulas; it is enough to simply assume that the lens aperture of 1.0 (length = diameter) means complete transmission of light. A lens aperture 2.0 means that the length is 2 times the diameter and only 1/2 of the light passes through. A lens aperture of 4.0 means only 1/4 of the light gets through, etc. These are conditional calculations, but they are quite sufficient to understand the process.

Note that the smaller the aperture or the longer the length, the greater the lens aperture. That is, large numbers indicate that the lens aperture is small, and vice versa.

The aperture of a lens is often referred to simply as "hole". For example, if they say “lens with a hole 2.8”, you need to understand that the lens aperture is 2.8. A lens with a hole aperture of 1.0 aperture (that is, an absolutely fast lens) does not exist in reality. The only model from Canon cost a lot of money and is no longer produced.

Despite the fact that all cameras have a lens aperture, there is a class of lenses with increased aperture, which are called fast. The fastest lenses are 1.2 aperture (rare and very expensive) or 1.4. 1.8 and 2.8 are more common. If the lens aperture ratio is more than 2.8, then it is no longer considered fast.

In addition to the hole itself, a special mechanism is built into the lens or into the camera itself - the aperture, which allows you to adjust the width of the hole. Naturally, the diaphragm can only make it smaller, but not larger than it is initially. Often, aperture and relative aperture are considered the same thing. For example, they say, “a lens with an aperture of 2.8” is the same as “the aperture of a lens is 2.8” or “a lens with a pinhole of 2.8”. However, the difference between the diaphragm is precisely that it is a mechanism that regulates the hole. Using a diaphragm, you can make a 5.6 or even 44 hole from a 2.8 hole (remember that the higher the number, the smaller the hole). What is this for? In photography, it is important to control the amount of light hitting the film or sensor, and aperture is one of the controls. In addition, other effects can be achieved using the diaphragm.

To summarize, we can say that the larger the lens aperture, the better. After all, if necessary, the hole can always be reduced with the help of a diaphragm, but you can’t make it bigger.

The lens aperture is determined by the numbers written on it. The lens aperture is always indicated in conjunction with the focal length (since the aperture is relative). For example: 50mm f/2.8. In this case, f means focal length, and f/2.8 is precisely the relative aperture. For brevity, they often write simply 50/2.8.
There are other designations: for example, 4/50. In this case, the lens aperture is indicated first, then the focal length.

For zooms, the lens aperture can be constant or variable. Since the zoom can be extended, the ratio of length to diameter changes accordingly. In this case, the aperture of the zoom lens is indicated in pairs, as well as the focal length, for example, 24-135 mm f/3.5-5.6. This means that at 24 mm the lens aperture is 3.5, and at 135 mm the lens aperture is 5.6, and there is something in between. For higher quality and more expensive zooms, the lens aperture is constant throughout the entire range. Then it is indicated by one number, for example, 28-70/2.8 or 70-200/4.

We all know that fast lenses are good. Firstly, you can shoot in low light, without having to raise the ISO or lengthen the shutter speed. Secondly, you can get an artistic effect in photos and videos - due to the shallow depth of field and beautiful background blur. Many of us have f/1.8 lenses, some have f/1.4 or even f/1.2 lenses. We know that “one” is not the limit, we have heard about lenses with f/0.95 aperture (and some lucky people have them at their disposal). There are rare models with f/0.8 on the market. What is the maximum aperture ratio a lens can theoretically have?

Dedicated to this topic video Matt Granger.

Matt says that just as there is a race for high ISOs now (and a little earlier, a race for megapixels), so in the 60s and 70s of the last century there was a race for high aperture. Here's a Zeiss 50mm F/0.7 lens that was made for NASA:

Legendary director Stanley Kubrick used this lens in 1975 to shoot a scene in Barry Lyndon lit entirely by candlelight.

And here is a lens with an aperture of f/0.33. It was made in the 60s, again by Zeiss, and was named “Super-Q-Gigantar 40mm f/0.33”, where Q is short for Quatsch, which in German means “nonsense, nonsense, stupidity”. Unofficially, he was teased as “Frankenstein.”

In fact, this lens never worked, it is essentially a weight-and-size mock-up created for promotion and to gauge public reaction.

But what could be the maximum aperture - theoretically?

Since the formula defines aperture as the focal length divided by the maximum aperture, it is theoretically possible to make a lens with a focal length of 35mm and an aperture of 350mm - please, that would result in an incredible f/0.1 aperture.

The trouble is that “theoretically possible” and “practically realizable” are in this case two things very far from each other. After all, we are talking about a lens with an aperture of 35 centimeters (that is, the diameter of the outer lens and frame will be even larger), which will also be very heavy. The depth of field will not even be measured in millimeters, but in insignificant fractions of millimeters; the remaining areas will be greatly blurred. It’s hard to imagine why such a lens would be needed in practice.

Matt Granger talked with the Zeiss developers, and they confirmed that, in principle, if you do not take into account issues of cost and practical use, such a lens can be made. But it will turn out to be prohibitively expensive.