What is ISO and why do we need to know it? Extended ISO range: a really useful feature or a clever marketing ploy

Most cameras, with the exception of inexpensive point-and-shoot cameras, provide the ability to manually adjust ISO. And if this abbreviation does not raise questions among professional photographers, not all amateurs know about this important parameter in photography. In what shooting conditions it may be useful to use the manual ISO setting mode in the camera, we will describe below.

ISO of a camera is a quantitative indicator of the sensitivity of the matrix to light, meeting generally accepted standards specified by the manufacturer. The abbreviation has the following meaning: International Standards Organization. The photosensitivity indicator is determined by lighting conditions and is indicated on the camera in whole numbers 100, 200, etc. The range of available values ​​may vary by model. For manual adjustment of exposure parameters - shutter speed and aperture - selecting the appropriate sensitivity value is an important point.

When setting low sensitivity values ​​within 100, for example, to get a good shot good lighting required. With low values ​​of the sensitivity parameter and the correct choice of exposure pair, the pictures are clear and crisp.

Advice! When shooting in good light conditions, you should follow the rule: low ISO = high image quality.

This rule is clearly illustrated by an example of images taken with different sensitivity settings: 100 (left) and 3200 (right). In the frame on the right, grain (digital noise) is more noticeable.

Relationship to Other Exposure Options

Changing ISO directly affects shutter speed and aperture values. With automatic settings, the camera itself selects the optimal exposure pair. Manual configuration assumes that the user will make this choice. Before setting the parameter, you should consider the following important points:

• lighting level - whether the subject is sufficiently illuminated;
• frame dynamics (a stationary or moving object is filmed);
• work out options for leveling noise in low light if graininess in the frame is undesirable;
• Using a tripod will help stabilize the frame during long exposures.

Examples of using different parameter values

For shooting on a clear sunny day professionals recommend using a standard of 100 or lower, but not higher than 200. The low sensitivity of the matrix in bright light ensures good image quality. The sensor sensitivity value of 100-200 is usually used for studio filming.

When shooting outside on cloudy days, as well as in the shade or indoors without additional lighting, the optimal parameter values ​​will be ISO 200-400. You can raise the setting a little higher when shooting at twilight: the recommended limits are 400-800.

Important! At ISO 400 and above, noise begins to appear in photographs. And the more there are, the worse the image quality. You can neutralize the impact of noise by selecting the aperture and shutter speed, and using a tripod to stabilize the frame.

You have to work with higher ISO values ​​- 800 and above - in the following cases:

• shooting children on a moving carousel and other moments with dynamic movement of objects in the frame;
• on an excursion to a museum, at a concert or theater, or in other rooms where the use of a flash is prohibited;
• when photographing memorable moments (blowing out candles on a cake, kissing newlyweds, shaking hands, etc., when using the flash is distracting);
• filming sports competitions, demonstrations and marches;
• night shooting.

The camera of the phone and camera provides automatic setting of the matrix sensitivity to light parameter. This mode is convenient to use when there is no time to experiment with manual settings in order to obtain artistic photographs. As a rule, selfie lovers also use automatic settings.

Any digital photographic equipment is marked with numerical indicators. Along with the matrix resolution, zoom factor and other parameters, the available sensitivity range is indicated. This parameter only indirectly reflects the camera's ability to shoot in low-light conditions.

Very high ISO, declared by the manufacturer on compact-sized devices with small photosensitive elements (matrices), is an option useless in practice. Due to the high level of digital noise at such values, the images will appear as a red-blue mess of dots with a barely visible image of the object. The figure illustrates the level of sensitivity of the matrix at different values ​​of sensitivity to light.

In addition to the ISO range, it is important to pay attention to sensor size. All other things being equal, the noise level in the image will be lower. But it is worth remembering that the better the matrix, the more expensive the camera.

Advice! For amateur photography, a maximum sensor sensitivity of 3200 is sufficient.

Most modern digital cameras offer users the ability to choose between using the native ISO range and an extended ISO mode.

Experienced photographers understand well which camera functions are really useful and which are practically not used in their work and were added by the manufacturer as a marketing ploy. Beginners, when choosing a camera, can easily get confused in all the variety of options, for example, what is ISO and how to choose the right working ISO range.

Choose between native and extended ISO range

When changing the ISO value on a digital camera, the user adjusts the signal strength, thereby changing the ratio of forced gain to the light-receiving ability of the sensor. There are certain minimum and maximum ISO gain values ​​- this range is called standard. Once the standard values ​​are reduced or exceeded, the camera sensors will not be able to adequately read the data.

Until some time, the upper threshold of the photosensitivity value was considered unshakable, but the rapid development of the hardware and software of modern cameras has allowed us to reach incredible heights. The same applies to the lower value of the ISO range - modern technology can significantly reduce it. In essence, taking photos using an extended ISO range is similar to post-processing a photo on a computer, only this process takes place directly in the camera itself.

How an increased ISO range can affect your photos

Cameras with a large ISO range use sensors with standard light sensitivity, the same as those found in conventional cameras. Extended ISO ranges such as ISO 12800, ISO 25600, ISO 51200, ISO 102400 are achieved by using conventional sensors and electronic circuits whose light sensitivity is enhanced using software. It follows that the extended ISO range is nothing more than a marketing ploy.

Claims that a camera can shoot up to ISO 102400 are impressive for budding photographers, but that doesn't mean that when they buy a camera they're buying a sensor with such high light sensitivity. In fact, these values ​​are achieved thanks to software, and often manifest themselves in low-quality images with a lot of digital noise.

Photos taken at extremely high ISOs will only look good in black and white, negating that advantage of cameras with extended ISO ranges.

An attentive user will definitely notice that the camera in the extended ISO range takes frames in JPEG format, but not in RAW. This is due to the fact that when shooting in RAW mode, a digital negative is formed with minimal processing, as this expands the possibilities for post-processing frames using photo editors. (It is worth mentioning, however, that some manufacturers allow the possibility of using an extended ISO range when shooting in RAW format.)

There may be some benefit to using a larger ISO range for JPEG photographers who do not post-process the images. It is still necessary to take into account that you will have to close your eyes to quality.

Everyone who has a camera in their hands sooner or later decides to delve into its settings, sees a completely unfamiliar abbreviation there and wonders what ISO is in a camera. However, in reality, everything is not as scary as it might seem.

General concept

What is ISO in a camera? This is an indicator of how sensitive the light-collecting element of the camera is to the flow of light entering it. The higher this value, the less demanding the device is regarding the level of lighting when shooting, that is, it can be used to shoot in dimly lit places.

The ISO sensitivity of a camera was typical for film models, but now this parameter characterizes the matrix rather than the film. The value is indicated in whole units, and the maximum and minimum permissible values ​​for each model may vary depending on the presets provided by the manufacturer. The ISO number in the camera is very important when correctly setting the exposure pair, that is, the shutter speed and aperture values. Sometimes even choosing the optimal combination of these indicators does not allow you to get a frame with the correct exposure: either there is an excessive amount of light, or the picture turns out to be very dark.

How to use?

What ISO is in a camera is clear in general terms; now we should talk about the possibilities of its use. When changing its parameters, you can additionally adjust the sensitivity of the matrix in order to equalize the exposure of the future photo without using a flash. To change the photosensitivity indicator, the following stops are used: ISO 100, ISO 200, ISO 400, ISO 800 and so on, depending on the model. Each subsequent stop represents double the difference between the previous two. Some higher-end models allow you to set intermediate values ​​manually - ISO 250, ISO 500. If the selection is carried out automatically, different values ​​can be used: 1400 and 240.

Operating principle

So, having understood in general terms what ISO is in a camera, it is necessary to decide on the principle of its operation. This can be done with an example. The subject is a street with poor lighting. Shutter speed - 1/20. Aperture priority mode. ISO 100. These settings ensure that the frame is blurry in most cases. This is due to the high shutter speed. That is, the camera remains open longer, managing to catch a lot of light. To avoid this, you need to lower the shutter speed, but increase the light sensitivity, which will prevent the picture from becoming dark. If the ISO is 800 and the shutter speed is 1/160 of a second, then you can shoot an evening landscape without a tripod, and the frame will still be clear.

"Noises"

You already have an idea of ​​how to adjust ISO on your camera, but this does not mean that by setting the value to maximum, you can automatically relieve yourself of worrying about the quality of the resulting image. If the indicator is too high, then the photographer will face a completely different kind of problem - a large amount of “noise” will appear in the picture. These are colored dots, from which the quality of the image is noticeably poor. Where do they come from? The thing is that an increase in the level of the electrical signal automatically leads to increased interference, which are extraneous signals that have nothing to do with the subject being photographed. The matrix itself also creates a certain level of “noise”. You should not use maximum ISO values; it is better to stick to neutral values ​​of 200-400 for regular cameras and 400-800 for DSLRs. And the lower these indicators are, the better.

Digital cameras must be used in certain ways to ensure good quality photos. ISO should be reduced to a minimum when shooting, and setting the shutter speed and aperture allows you to select the necessary exposure parameters. Only in the case where it is impossible to change these values ​​is it necessary to increase the light sensitivity.

Which ISO should you choose your camera with?

The choice of camera should be based on certain recommendations.

Digital cameras are necessarily characterized by a maximum and minimum ISO value. This is what you should pay attention to. You should not chase large values, since in practice they are unlikely to be useful. If you make a choice in favor of such values, then you should consider professional and semi-professional models as a purchase, since their large matrix size does not allow “noise” to appear in the photo in large quantities. It is desirable that there is an ISO button on the camera, then it will be more convenient and faster to set it up. However, in “soap dishes” there is usually no such option, and you need to get to the parameter through a multi-level menu. In this case, it is important to remember the sequence of actions.

Features of models with an extended photosensitivity range

On cameras with a high ISO, the “noisy” effect in the pictures will be very noticeable. Most often, buying such a camera turns out to be pointless, unless you print small-sized pictures, where the “noise” is not very noticeable. If the photosensitivity is extended to a low range, then you can work with longer shutter speeds, and the image becomes less “noisy”, but a certain amount of contrast is also lost.

A high ISO value may be required at children's parties, sporting events, where shooting is done at minimum shutter speed, since in other cases the risk of getting blurry photos is too great. For example, in places where there is a ban on the use of flashes, when photographing memorable moments, in particular kisses, blowing out candles on a birthday cake and others. If there is a flash, the impression of these moments may be ruined.

conclusions

So, ISO is just the degree of sensitivity of the matrix to light. The higher this value, the higher the sensitivity, as well as the more “noise” in the image, and vice versa. When shooting, it is best to lower this indicator to a minimum, combining it with the aperture and shutter speed values, which will allow you to get the desired effect. If shooting is done in high-quality lighting conditions, then ISO is set no higher than 100-200. For cameras with a larger matrix, you can set higher values, as they are less susceptible to “noise”.

Photography is not just a set of strict rules, it is also a space for creativity, so everyone can choose the values ​​they need. The guideline in this case is based on taste preferences and technical capabilities. But the main desire should be for the harmony of the photo. If this is achieved through an unexpected experiment, then the skill of the photographer can be proven.

Instead of the name ISO, they often say photosensitivity. This name better describes the purpose of this parameter. ISO is a measure of how sensitive it is to the light thrown at it. A higher ISO value makes the sensor more sensitive to light, so higher values ​​are used for shooting in low-light conditions. Modern digital cameras can take pictures at different ISO settings, which will be recorded on a single memory card. Previously, photographers had to change film to change ISO.

When should you increase your ISO? For example, the camera cannot set a normal exposure. The lighting is too dim for him. Sometimes you can use the flash, but it doesn't always help. For example, when photographing at a concert, it is not always possible to use a flash and it will not always help. In this case, you need to increase the ISO manually or set the sensitivity to automatic selection mode.

Increasing ISO makes it possible to reduce shutter speed. This will help get rid of movement or allow you to take normal shots in cases where a tripod would be needed at a lower sensitivity value.

Noise and ISO.

Increasing ISO is not only positive, but also negative. Increased sensitivity to light will certainly lead to the appearance of noise in photographs. This is caused by this. that the matrix, along with the useful light signal, begins to perceive minor interference and distortion. In addition, the matrix itself does not convey a 100% ideal image. Increasing sensitivity to light increases errors that are caused by leakage currents between pixels.

All sensors are tuned to transmit the least amount of noise at the lowest ISO settings. In most cameras this is ISO=50, 80 or 100.

Noise in digital photographs is similar to grain in film photographs. This effect is highly undesirable. It appears as colored dots that are distributed throughout the frame.

Relationship between ISO and matrix size.

The physical size of the sensor determines the quality of images that will be obtained at certain ISO values. This is caused, first of all, by the fact that on large matrices the pixels are larger than on small ones, and therefore perceive more light. For example, two 4 megapixel matrices with different sizes and the same settings will show different noise results. The matrix that is larger will make less noise.

Is it possible to take photographs with high ISO?

Until all cameras have larger sensors, image noise will be very noticeable and therefore a problem.

Relatively recently, cameras called semi-professional have appeared on the market. They have larger matrices than compacts. Such cameras will have less noise, but only if the number of megapixels is not too large. Don't fall for advertising that says the more megapixels the better. This is wrong. Everything should be in moderation.

Light noise will not be noticeable in pictures if they are printed small. There are special programs and plugins for Photoshop that significantly remove noise from images. Among such programs are: Noise Ninja, Neat Image and many others.

Situations may often arise when the choice is between taking a photo with a high ISO value or not taking a photo at all. In this case, it is better to take a picture and try to remove noise on the computer. Plus, not all noisy photos look bad.

Conclusions.

• ISO is a parameter that determines the camera's light sensitivity.
• The highest quality images are obtained at the lowest ISO setting. In order to make sure that the lowest value is set, you need to switch to manual mode and make sure of this.
• When shooting indoors in low light, the choice becomes to use flash or studio lighting or raise the ISO. Noise will appear differently for different cameras. The degree of noise depends on the size of the matrix.
• Matrices with a larger physical size will allow you to shoot at a higher ISO without losing quality. In addition, this will allow you to reduce the shutter speed and thereby get rid of movement and blurry photographs.
• When printing photos of small sizes, the noise is almost unnoticeable.

Every camera owner has undoubtedly come across such a parameter as ISO. And all publications on photography are full of phrases “ISO level”, “ISO sensitivity”, “photo sensitivity of the matrix”. What is this quantity, and what values ​​should it take? Let's deal with everything in order...

What is ISO?

ISO is the camera's sensitivity to light. This parameter, along with shutter speed and aperture, affects the exposure of the resulting photographs. Therefore, learning how to set optimal ISO values ​​for different shooting conditions is very important.

The ISO value is measured in 1/(lux×second). As a rule, the scale starts at 100 and increases twice to the maximum level possible for a particular camera.

The minimum and maximum ISO values ​​are important camera characteristics. Most modern devices, in addition to standard values ​​(100, 200, 400...), also have intermediate values, which allows for more precise camera settings.

At a low ISO the exposure will be low, increasing the value of this setting will result in stronger light exposure and longer exposure. Thus, increasing the ISO causes an increase in light sensitivity and causes noise to appear in the photograph. Therefore, try to always shoot at a low ISO to ensure clear, grain-free images.

It is important to remember that the exposure of photographs is affected not only by ISO, but also by the aperture and shutter speed settings. By manipulating these parameters, you can obtain enough light to create a clear image. So, to compensate for the increase in ISO, you will need to reduce the shutter speed or close the aperture and vice versa.

Incorrect shooting settings can result in noisy photos. Grain reduces the detail of photos and makes the image uneven. You can correct the situation in a software editor, however, noise reduction is often done by shading small details, which is not always appropriate.

Having understood what ISO is, all that remains is to understand what values ​​of this parameter will be appropriate in different shooting conditions. So:

• The lowest ISO setting produces the best results. This is what you should choose when shooting in the studio and outdoors in clear weather.
• If you plan to shoot in low light, it is best to increase the ISO value to 200-400, especially when you cannot use a tripod. Indoors, when working with flash, values ​​of 400-800 are acceptable.
• It is advisable to use indicators above 800 when photographing public events, club or reportage photography in low light conditions. In such situations, there is usually no choice, and to get clear frames you need to set a high sensitivity value.
• ISO 1600 and higher will help you get good shots at a concert when the photographer is in the audience and cannot use a tripod. Higher sensitivity values ​​are intended for very low light conditions, but are often impractical to use due to the appearance of strong noise in images.
• If you plan to shoot staged at night, it is best to use a tripod and set the ISO to a low value. This will help you get expressive shots with low grain.

The amount of noise in a photograph at high sensitivity values ​​depends on the size of the matrix of the camera used. Soap cameras, even at ISO 800, are not capable of producing good results, so it is better to set a low ISO and use a tripod. But expensive DSLRs with an indicator of 3200 and above give excellent results, and with them the feeling that the money was well spent.

In addition, do not forget about the Auto ISO function. Beginners often use it so as not to bother with choosing parameters. But this function is very capricious. On point-and-shoot cameras it does not give the desired results, so it is better to manually set ISO 100. In DSLRs, it is advisable to set a threshold beyond which the ISO parameter should not go, for example, 800, and within this framework let the camera itself choose the optimal shooting mode.

Conclusions:

ISO controls light sensitivity and noise levels. It is best to take photographs at the minimum values ​​of this parameter and reduce them as soon as possible. Opening the aperture completely will help you lower your ISO as much as possible. But the lower the photosensitivity index, the longer the shutter speed.