Artem Kashkanov, 2012

We continue to test lenses for cropped Canon DSLRs. Last time, the objects of our study were. Today we will go up a notch and try to choose a fast standard zoom lens from the class of semi-professional lenses from Canon, Sigma, Tamron. As subjects, we will choose 5 lenses, the range of focal lengths for which starts from 17 mm, and aperture from f / 2.8 (with the exception of the Canon 17-40mm f / 4L, it is present here to compare "ordinary" lenses and those comparable in price and scope "elek").

This article will compare the results obtained during laboratory testing of the following lenses:

Learn more about lenses

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The aperture ratio of a lens refers to its ability to transmit light. This ability directly depends on the maximum value of the relative aperture of the lens, i.e. from the minimum available aperture value. Strictly speaking, such a luminosity is called geometric, since it takes into account only the geometric dimensions of the aperture opening and ignores the attenuation of the light flux by the objective lenses, but such a simplified approach is quite suitable for comparing different lenses with each other. Therefore, when photographers talk about lens aperture, they usually mean the minimum aperture number and only that.

Obviously, a faster lens at equal ISO values ​​allows you to use faster shutter speeds than a less fast one, and at equal shutter speeds it makes it possible to lower the ISO (see "Exposure").

In English literature, the term “lens speed” is common, denoting the same minimum aperture number. Fast lenses are called fast for the ability to shoot with high speeds shutter, and also for the speed with which they empty the photographer's wallet. The lenses of high-aperture optics are impressive in size and require a large number expensive optical glass, which translates into a significant increase in the cost of the lens.

What lenses are considered fast?

Professional fast zoom lenses have a minimum aperture of f/2.8. Lighter and cheaper zooms have a minimum aperture of f/4. The latter is no longer customary to call aperture. Both f/2.8 and f/4 zoom lenses feature constant aperture throughout the entire zoom range, i.e. at 70-200mm f/2.8 zooms, f/2.8 will be available at both 70 and 200mm.

Amateur "dark" zoom lenses have a variable aperture in the region of f / 3.5-5.6, i.e. the minimum aperture value at wide-angle is f/3.5 and at telephoto is f/5.6. Variable aperture allows you to reduce the size and cost of the lens.

Fixed focal length lenses are much faster than zoom lenses. Here you will not surprise anyone with an aperture of f / 2.8. A fixed lens becomes truly fast at a minimum aperture value of no more than f / 2, and for professional fixes, aperture reaches f / 1.4 or even f / 1.2. Some specialized lenses (for example, for astrophotography) can have apertures up to f / 0.7, but such optics cannot be called mass-produced.

The reason for such a significant difference in the aperture ratio of lenses with variable and fixed focal lengths lies in the relative simplicity of the design of prime lenses. Optical zoom schemes are very complex, including dozens of lenses from different types of glass, which makes it very difficult to achieve apertures above f / 2.8.

I hasten to remind you that we are talking about geometric luminosity, which does not take into account the absorption of light by a particular lens. The difference between effective aperture(taking into account the absorption index) of lenses with fixed and variable focal length is even greater than the difference between their geometric aperture, which is due to the large number of optical zoom elements, and hence the greater loss of light on the way through a complex lens.

There is a belief among beginner amateur photographers that the higher the aperture ratio of the lens, the better. Is it so? Yes and no.

A fast lens really allows you to use faster shutter speeds, which is indispensable when shooting moving objects in low light conditions, whether it's athletes in a dark room or wild animals at dusk. But when you shoot a static landscape, and even with a tripod, shutter speed stops worrying you. When shooting running water, you want to increase the shutter speed at all. And for a landscape photographer it is rather tiring to carry heavy aperture glasses with you in the mountains.

In other words, there is nothing wrong with fast optics, but for solving most ordinary and series professional tasks apertures above f/4 (for zoom lenses) or f/1.8 (for prime lenses) are, to put it mildly, redundant.

If you definitely want to shoot at wide apertures, then you can start by acquiring a classic fifty dollars, i.e. lens with a focal length of 50 mm. Being a normal lens for full-frame and 35mm film cameras, on cameras with a crop factor (Nikon DX, Canon APS-C, etc.), a fifty-kopeck piece turns into a short telephoto lens, very convenient for shooting portraits. With f / 1.8 aperture, such lenses are not at all expensive, and the quality of the optics is very, very worthy. This is the easiest and most budgetary way to try high-aperture optics, so to speak, to your taste, and decide whether, in principle, you personally need a large aperture.

Thanks for attention!

Vasily A.

post scriptum

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Lens aperture- this is one of the main parameters that you should pay attention to when choosing a lens (along with ). The luminosity of the optical system shows the degree of attenuation of the light flux. In other words, the luminosity shows how much of the light flux the lens system of the objective is able to pass through.

The fact is that part of the light flux passing through the lens is scattered and reflected from the lenses, part of the light is absorbed by the material from which the lenses are made (glass, optical plastic). Therefore, the luminous flux is attenuated due to these purely physical characteristics.

So, by buying a lens with a larger aperture, you will be able to open the aperture more. So you can skip large quantity light (it becomes possible to shoot in low light). Also, the more the aperture is opened, the smaller the depth of field in the frame is (the objects that are not in the focus area are more blurred). That is why f1.4-f2.8 lenses are considered good portrait lenses.

You may notice that manufacturers of photo optics produce a line of lenses with the same focal length, but different aperture ratios. Moreover, the greater the aperture ratio, the more expensive the lens costs, and the increase in cost is significant. For example, let's compare the prices of Canon lenses with a focal length of 50 mm. So, a 50 mm 1.8 lens costs 3,500-4,000 rubles, a 50 mm 1.4 lens costs about 13,500 rubles, and a 50 mm lens with aperture ratio of 1.2 is sold at a price of almost 48,000 rubles. Data are current as of February 2013.

As we found out, in most cases the larger the aperture of the lens, the better, because:

— you can shoot in the worst lighting conditions;

- you can shoot with a smaller depth of field.

On the other hand, you need to pay a lot of money for additional aperture. Therefore, when choosing a lens, weigh the pros and cons.

Choose your lens wisely and enjoy your shots!

Many amateur photographers tend to purchase a fast lens for their camera kit. With the right help, you can capture beautiful portraits, beautifully blur the background and paint bokeh, or shoot in difficult low-light conditions handheld without carrying a bulky tripod around. The market now offers quite a wide variety of models of high-aperture glasses. Their choice depends only on the capabilities of your wallet and your own desire.

But sometimes there are superluminal specimens. And although they are not always sharpened for photography, but the value of their aperture makes them admire these monsters. Our TOP includes 10 lens models whose aperture value is less than f / 0.8.

1. GOI CW 20mm f/0.5

The mirror lens was produced in the USSR in 1948 by the State Optical Institute. The f/0.5 value is, in fact, the theoretical limit of lens speed. And it was our opticians who, in the difficult post-war years, created a super-luminous optical system. After that, various delegations came to the USSR in order to learn from experience, but no one has dared to repeat such a design since then.

2. Signal Corps Engineering 33mm f/0.6

This lens, produced in the post-war period for the US Signal Corps by German scientists transported to America, was supposedly intended for night vision or X-ray use. The sticker on the lens reads “ World's Fastest Lens“, which means “The fastest lens in the world”. Who knows, maybe at that time he was.

3. GOI Iskra-3 72mm f/0.65

Follower number 1 on our list was also released by the bright minds of the USSR. By its design, it is a mirror, and it was used in the field of radiography.

4 Carl Zeiss Planar 50mm f/0.7

For some reason, this lens is considered the most aperture in the world. Although, as we can see, he is only in 4th place in our TOP. Designed in 1960 specifically for NASA's mission to photograph the dark side of the moon, the Carl Zeiss Planar 50mm f/0.7 was only produced in 10 examples. But only 6 of them were transferred to NASA. Another copy remained in Carl Zeiss, and the remaining 3 were sold to the famous director Stanley Kubrick. He used them to shoot the candlelight scene in Barry Lyndon (1975). You can also feel like Kubrick - P + S Technik rents out a lens in conjunction with a PS-Cam X35 HD camera, which anyone can use.

5. Fujinon 50mm f/0.7

Glass from the Japanese brand Fujifilm does not indulge in information about itself. So we will be glad if someone buys it for their Nikon or Canon and shares their impressions. Fortunately, at various auctions it is sold at quite affordable prices - in the range of $500-$600.

6. Irtal-3 100mm f/0.7

The most long-range representative from our list. 100mm at f/0.7 is respectable. But you will not be able to use the lens in the classical sense of the word, since its optical component is made of pure germanium, which does not transmit visible rays. This is an infrared lens and can be used as a thermal imager.

7. Carl Zeiss Jena R-Biotar 100mm f/0.73

This copy was previously used on old X-ray installations. Those that had a fluorescent screen. Those. they did not print pictures, but allowed to see through a person only in real time. In order to reduce the radiation dose and obtain the fastest image, it was desirable to increase the aperture ratio, for which this hero came in handy. You can read more about the lens at the link.

8. Leica Leitz 65mm f/0.75

Like the previous model, most likely this Leica was used in the field of radiography. But some people still saw color photographs taken with the lens. They were mostly pictures of flowers. close-up. Naturally, the depth of field of the images was very small, but in the focus area the picture looked very even nothing.

9. Rodenstock TV-Heligon 50mm f/0.75

Initially, the German-made lens was also intended for X-ray use. But many craftsmen adapted it for use with cameras, which the manufacturing company itself took advantage of. Now, at various online auctions, this medium format glass can be purchased for a wide variety of mounts - Nikon, Canon, and even Micro 4/3.

10. Canon TV-16 25mm f/0.78

The last copy on our list has a soft focus, can draw beautiful bokeh and conveys colors remarkably. But it has pronounced vignetting. Although if you use glass for its intended purpose, i.e. as a portrait painter, in many cases this will only work to your advantage.

Instead of a resume

Nowadays, few people need lenses with such aperture values. After all, they have the main significant drawback - very small zones of sharpness. But progress is inexorably striding forward, and who knows what it will lead to in a couple of years? .. Maybe such models will still get into mass production.

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

If everything is greatly simplified, then the F number (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 F number is called geometric luminosity. In fact, luminosity- this is the ability of the 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 an ideal lens with a T number of 2.0 would match it. You can use the T number in the same way as the F number.

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 density 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.

I have found information on the web that photographers are deceived, indicating on the lens body is not the real aperture value. 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, where more accurate and faster to handle the auto focus system.

Roughly speaking, the stronger the light flux from the lens to the mirror, the easier it is for the phase focus sensors to focus. I first felt the difference when shooting for a long time in the studio, where I had at hand a weak modeling light from the lighting. 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.

Who does not know, then modern reflex 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.