Did you know that depending on the characteristics of a particular camera and lens, the available shutter speed and aperture values change, and it may happen that you cannot find the right exposure pair
If you do not have the opportunity to set the desired exposure pair, you will not be able to get a correctly exposed frame: o (What to do? Will the frame be spoiled by the wrong exposure?
In this photography lesson, we will "ask for help" from International Organization on Standardization: o) No, we will not write a letter to this organization asking for help! She has already helped us by coming up with an appropriate film speed standard.
Historically, the speed of photographic film, without any changes, has been used in digital photography, for which film is not needed. So ISO is just an acronym. English name the organization mentioned above: International S tandardization Organization - ISO for short.
ISO in a digital camera and photography in general indicates the level of sensitivity of the pixels of the photo matrix. We will be interested in the numbers after the three ISO letters.
The values of these numbers correspond to the sensitivity of the film or camera matrix.
Higher ISO numbers correspond to greater sensitivity of the camera's matrix. Just like for the sensitivity of the matrix of a digital camera or film, it has standard values, i.e. on all cameras, these numbers will be the same:
Table of standard film (matrix) sensitivity values:
| 100 | 200 | 400 | 800 | 1600 | 3200 |
You noticed that we are again dealing with standard values, just like standard shutter speed and aperture values - i.e. any adjacent standard value changes the exposure by one step. If you don't remember, remember
CHANGE THE EXPOSURE by adjusting the ISO,
by clicking the buttons below the picture
ISO settings
Noticed? The shutter speed and aperture did not change, and the exposure changed from -2 to +2 stops thanks to ISO settings. In your camera, this range of settings can be even greater!
If you shoot with high sensor sensitivity, then even when photographing indoors you can do without a flash - a miracle? In fact, it is not so simple professional photographers use high ISO values with extreme caution, because they understand what the sensitivity of the photo matrix is.
What is matrix sensitivity
The lens of your camera rested on the value of f / 4 and nothing more. To set the correct exposure parameters, we did not have one stop of the aperture!
This is exactly the case when you need to adjust the ISO. For example, in the table below, in the first column, our initial shutter speed and aperture values \u200b\u200b(when one aperture stop was not enough). We increased the sensitivity of the matrix by 1 step, while the aperture and shutter speed remained the same, and the exposure (bottom line of the table) became acceptable for our conditions - the second column of the table. If we keep increasing the ISO, we can shoot at a faster shutter speed or close the aperture if we want to increase the depth of field.
Here are the equivalent camera settings
| 1/125 | 1/125 | 1/500 | 1/500 | 1/1000 | 1/1000 |
| f/4 | f/4 | f/4 | f/5.6 | f/5.6 | f/8 |
| 100 | 200 | 400 | 800 | 1600 | 3200 |
| -1 | 0 | 0 | 0 | 0 | 0 |
You may have noticed that the product of the square of the aperture denominator and the shutter speed denominator
divided by ISO sensitivity is a constant number for given shooting conditions:
(4² × 500) : 200 = (4² × 250) : 100
Curious mathematicians can do research: o)
By changing the sensitivity of the matrix (ISO), we replace the missing ones for
normal exposure equivalent to the shutter speed (and/or aperture) stops.
During photography, ISO is usually set to the minimum value. And only when it is impossible to achieve the correct exposure by adjusting the shutter speed and aperture (there is not enough light) or the photographer has decided to take an expressive picture and he needs specific shutter speed and aperture settings, you have to adjust the exposure with the ISO settings.
To visually study all the intricacies of the interaction of shutter speed, aperture and ISO, I suggest you practice on
Have you ever wondered: "what's happenedISO in my camera?
Or maybe not so long ago, 10-15 years ago, you bought film. On the counter, the choice was then ISO 100, ISO 200, ISO400. With little understanding of this, many took the most expensive ISO400, in the hope that their photos would be better. And when for black and white photography there was a film of 32, 64, 130, 250 photosensitivity units.
The characteristics of modern cameras indicate an ISO sensitivity of 100 and higher. On some professional cameras, ISO sensitivity goes up to 102,400.
What isiso?
Today we will do without goodies. We just finished the pie yesterday. Was very tasty
ISO or light sensitivity is the sensitivity of the camera sensor to light!
The higher the ISO value, the greater the sensitivity of the camera sensor and vice versa, the lower the ISO value, the lower the sensitivity of the camera sensor.
How does this affect photography?
Everything is very simple.
I spoke in a previous article about . It is necessary to use a shorter one so that there are no smears and movement in the photo. But sometimes we shoot in the evening, or in a room with low light. Camera automation is forced to use long to get a normal exposure. As a result, we get smears in the photo, the image is fuzzy.
So here on help will come ISO sensitivity.
We can raise the valueISO and then it will be possible to use faster shutter speeds and protect yourself from blurring in the photo.
But do not get carried away and use the maximum values. At high ISO values, color noise appears in the photo. The following are examples of photographs different meanings ISO:
If you look closely at the pictures, especially at 100% magnification
It begs the conclusion:
The higher the ISO value, the more noise in the photo.
The lower the ISO value, the better the photo quality.
Can be used long exposure and the minimum ISO value - get a blur in the photo without noise.
You can use a fast shutter speed and maximum value ISO - get sharp photos, but spoiled by noise.
You can choose the optimal shutter speed and ISO and get a well-exposed photo without noise.
What are the meaningsISO to use to avoid noise in a photo?
During the day with good outdoor lighting, try to use the lowest ISO values. 100-200 units will be enough.
If you are shooting indoors with artificial lighting then you will have to use ISO 400, 800.
For night shooting on the street, in order to work out the background, it is also desirable to raise the ISO to 800-1600 units, if the camera allows.
Well, if you have to shoot a report of some kind of concert, and there the stage lighting is rarely good, then you will have to use even higher ISO if your camera supports such values.
Should I use the maximum ISO value?
NO not worth it. The higher the ISO value, the more color noise will appear in the photo. This is due to the increase in voltage on the sensor. Yes, and on films, too, the higher the ISO value, the greater the graininess in the photographs. True, it was noticeable only when printing large prints.
Permissible usage thresholdsISO
Modern digital cameras allow you to shoot at a value of 3200 - 12800. However, digital cameras have small matrices and they cannot give out really high photosensitivity. On such cameras, the camera processor is included in the processing. It crushes noise, but the detail of the picture is lost. Therefore, in poor lighting on digital cameras, the photos are very mediocre.
Modern DSLRs entry level and mirrorless cameras have a really working ISO of 800-1600 units. Cameras with a full-frame matrix produce a clear image without noise at 1600 - 3200 units, some professional models even at 6400 ISO produce an image of the same quality without noise as at 200 ISO.
Homework
1. Find in your camera how to adjust the valueISO.
2. Find the maximum valueISO that your camera can use.
3. Determine at whatISO produces photos of acceptable quality for you.
Write in the comments what model of camera you have, what is the ISO limit on your camera and what are the acceptable ISO values.
Your answers will be valuable to blog readers, they will help you choose the camera you need according to its characteristics.
I wish you less noise in your photos!
With respect, Roman.
It's very difficult to take really good photos without understanding what ISO is and how it works. As mentioned in previous articles, photosensitivity is one of the critical factors good shot from the technical side. (The other two are Shutter Speed and Aperture). Therefore, it is very important to know what it is in order to squeeze the best out of your camera and take worthwhile pictures, which it would be a sin not to brag about. And since this article is dedicated to beginner photographers, I will try to explain what ISO is as simply as possible.
1. What is ISO?
In essence, ISO is the level of sensitivity your camera has to the available light. The lower the ISO level, the less the camera is sensitive to light and vice versa, the higher the ISO, the greater the light sensitivity. The camera component responsible for changing the light sensitivity is called the "image sensor" or simply the sensor, and is the most expensive (well, almost the most expensive) part of the camera. The essence of the sensor is that it converts the light falling on it into an image that we see and call photography. With increased sensitivity, your camera's sensor can capture images in low-light conditions without using a flash. However, there is a “but” here too - the greater the photosensitivity, the more graininess, or the so-called “noise”, is observed in the photograph.A clear example of this: 
Each camera has its own base ISO ("Base ISO"), which refers to the most low level ISO, which achieves the best image quality and lack of grain. On most Nikon cameras, this is ISO 200, on Canon it is 100. That is, as planned, you should try to use the base ISO all the time in order to get photos without noise and the best quality, but this is not always possible, especially in low light conditions.
As I said earlier, usually ISO starts at 100-200 ISO, after which it increases exponentially (twice each time): 100, 200, 400, 800, 1600, 3200 and so on. That is, each time you change the ISO level by one value, you double the light sensitivity of the sensor. So an ISO level of 200 is twice as sensitive to light as ISO 100 when 400 is 2 times more than ISO 200. This in turn means that a ISO level of 400 is 4 times more than ISO 100; and ISO 1600 is 16 times more light sensitive than ISO 100. But what am I getting at? The fact is that if the sensor is 16 times more sensitive to light, then it needs 16 times less time to capture the image.
Examples of ISO and speeds:
- ISO 100 - 1 second
- ISO 200 - 1/2 second
- ISO 400 - 1/4 second
- ISO 800 - 1/8 second
- ISO 1600 - 1/16 second
- ISO 3200 - 1/32 second
So, referring to the table above, if your camera takes one second to capture a photo at ISO 100, then at ISO 800 you can take a photo in just 125 milliseconds! And if you delve into this, then with the knowledge of this, the worldview on the photography technique as a whole changes, because you can instantly capture the scene, literally “freezing” the action. Let's take this photo as an example: 
Black lionfish shot at ISO 800 in 1/2000 of a second
As you can see from the photo description, I shot this bird at ISO 800, and it took the camera sensor just 1/2000th of a second to capture it. Now imagine what would happen if I set ISO 100: in this case, it would take me 8 times more time, which is 1/250 of a second. That is, instead of a clear image, I would get a blurry picture, because in 1/250 seconds the bird would have had time to change its location greatly and spoil the picture for me. That is why it is so important to know the principle of operation of the sensor and light sensitivity.
2. When to use low ISO?
As often as possible. That is, in theory, you should always try to use the lowest ISO level in order to get good quality and noise-free pictures, especially if there is enough light around. In other words, you should use a low level of sensitivity in well-lit rooms or with sufficient natural light. Although sometimes a low ISO is used in dark rooms to increase the exposure time and create the “Motion Blur” effect. However, in such cases, you must take into account that the camera will take time to capture the scene, so be sure to use a tripod to ensure that static objects remain static, otherwise you will be eaten by a ghost!
Oh no! Ghost attack!I'm kidding of course. By the way, this is my nephew; the fact is that I was just testing a long exposure on it, using the lowest possible ISO, as a result of which the exposure time was equal to five seconds, during which my friend managed to become a “ghost”.
3. When should I use high light sensitivity?
You should increase the ISO level when there is not enough light around to capture something quickly enough. So, when I shoot indoors without a flash, I use more high level sensitivity than usual to achieve the effect of "freezing" the movement. Raising the ISO may also be required when you need a clear shot of a fast moving subject. For example, as with that bird, the photo of which you saw above. However, before increasing the sensitivity level, it is worth considering whether you are ready to sacrifice image quality.By the way, on the latest models of DSLR cameras there is an interesting option when shooting in the “Auto ISO” mode ( Automatic setting Sensitivity) that allows you to select the highest level of ISO that the camera can afford. So, for example, if I want to limit the level of grain in my photos and still rely on my camera, I set the barrier to ISO 800 and I can shoot with confidence.
That's all, and take into account that everything you read in this article is just basic knowledge about photosensitivity in cameras and its principle of operation, told by the most accessible way. Since actually explaining what ISO is is a very laborious task full of technical terms, so if you want to understand in depth what ISO is, I can advise you to read a few articles from Wikipedia.
ISO is the light sensitivity of your camera, or rather, the sensitivity to light perception of the camera matrix. That is, if the ISO is 200, then less light will enter the sensor per unit of time than in the same time with a ISO value of 3200. The higher the ISO sensitivity of the sensor, the clearer pictures you can take, but you should not assume that clearer pictures it's always good. The more ISO you can set on your camera, the better large quantity extraneous noise appears in your pictures.The standard ISO values are: 100, 200, 400, 800, 1600, 3200. And the noise that appears in the pictures is multi-colored bright points in the photographs, which are very different in color from the neighboring ones. This noise makes the image look like it was taken with a 0.3 megapixel camera on a 2006 phone.
However, a ISO system was for film cameras. V digital cameras this parameter seems to correlate with the obtained exposure of the pictures on it and similar characteristics of the film camera. Therefore, this parameter on digital cameras has completely become known as "equivalent ISO speed". And it is expressed in ISO units for a film camera for the convenience of photographers.
How to use light sensitivity correctly
If you are photographing in a lit place, where enough light can get on the camera matrix in a short amount of time, then you should set the ISO to a small mark. If the room is dark, or you are shooting late in the evening, then the ISO value should be many times higher. However, it is always worth taking a few test shots and finding the best solution.Please note that for pictures in dark time day, it is important to open the aperture so that more light can also enter the camera matrix. If you are working with a tripod and static objects, then it is better to set the minimum ISO, but increase the camera's delay. If you want to reduce the amount of noise in your pictures, you can also use a flash to add light to the photo.
Setting the sensitivity also depends on the size of the matrix of your camera, if you have a fairly simple camera without interchangeable lenses, then the most beneficial value for you is ISO 800. If you set this parameter higher, then any photo will be overwhelmed with unnecessary noise. On the SLR cameras who have best parameters shooting, ISO 1600 and 3200 can be used.
ISO is one of the three factors that determine exposure, along with aperture and shutter speed. In order to get the best quality from your photos, you need to know how each of the three settings contribute. Read this tutorial to gain more in-depth knowledge on how to use your camera properly and start taking professional photos.
Step 1 - What is ISO?
ISO (International Standards Organization) determines the sensitivity of the sensor in your camera, which in turn affects the exposure of your photos. The ISO scale usually starts at 100, and each subsequent value doubles up to the limit of the camera's capabilities: 100, 200, 400, 800, 1600 ... The start and end points of the range depend on the camera you are using. Majority modern cameras They also have intermediate ISO values \u200b\u200bthat are equal to 1/3 steps.
The International Organization for Standardization is responsible for widely used standards in various fields, but everything you need to know about ISO as a sensitivity parameter is listed below.
Step 2 - How does ISO affect exposure?
ISO is one of the three parameters that affect exposure, along with shutter speed and aperture. Aperture is determined by the lens, shutter speed by exposure time, and ISO by the properties of the sensor. To be more precise, ISO determines how the exposure of a photo changes when the sensitivity of the sensor changes.
The ISO scale is similar to shutter speed in that when the ISO is changed by a factor of two, the exposure also changes by a stop, and they are proportional to each other. Decreasing ISO corresponds to low exposure, increasing it will give more strong impact light, the exposure will increase. Much easier than aperture. The following is 6 photos for different meanings ISO: 100, 200, 400, 800, 1600, 3200. Aperture and shutter speed remain constant on all photos, only ISO changes. So you can see the effect of this setting on the photo. the ideal exposure is shown in the fourth photo, where ISO is 800.
As you can see, each setting affects exposure independently. But there are some consequences of using high ISO values.
Step 3 - How does ISO affect photo quality?
As a general rule, the lower the ISO, the higher the image quality. By doubling the ISO, you are essentially doubling the exposure, and doubling the digital noise as well. This noise reduces the detail in the photo, making the image grainy and uneven.
Low ISO = High Quality
To better show how ISO affects image quality, I took another series of photos, which is shown below. For the purposes of this experiment, I changed not only the ISO, but also the shutter speed and aperture so that the exposure remained constant, as a result it was easier to compare the quality of photos. Photos are displayed in the following order: 100, 200, 400, 800, 1600, 3200
As you can see, the higher the ISO, the stronger the noise, the more it spoils the picture. Exists special programs. that remove noise. They can correct the situation, but at the cost of some reduction in detail and smoothing out small details that mix with noise. This is clearly shown in the picture below (section of the image at 100% scale). Therefore, use noise reduction plugins with caution.
Cameras with big size the sensor is better because the sensor receives more light. But technology is improving and the difference between sensor size and noise is shrinking, especially when compared to cameras from years past.
Every camera is different, so I suggest you shoot with your camera in low light conditions to determine what maximum ISO you can use without sacrificing too much quality. Increasing the exposure during processing has the same effect as increasing the ISO, that is, it increases the noise, so make sure that you set the exposure when shooting correctly, without underexposure. In this way, you will avoid increasing the noise during processing.
Now that you know how ISO works, let's take a look at various situations practical application.
Step 4 - Which ISO and when to use.
ISO 100: Your photos will have best quality. Excellent for shooting in daylight as there is no need to increase the ISO. Shooting at 1600 in bright conditions is a waste of time as the photos will be noisy.
ISO 200 - 400: For slightly less lighting, such as in the shade or indoors if it is brightly lit
ISO 400 - 800: I use this range when shooting indoors with flash as it allows the background to come out better.
ISO 800-1600: Reportage and event photographers often have no choice but to use this range, as live events often take place in low light conditions and flash is either not possible or prohibited.
ISO 1600-3200: Again, event photographers use this range for concerts and also in low light conditions where using a tripod is difficult. This range is the highest on my camera, but I rarely use it as I'm not a fan of digital noise.
ISO 3200+: This range is reserved for extreme low light, but is very noisy and the image is too grainy.
Translator's note: modern models of professional cameras give quite acceptable quality for reportage shooting at much higher ISOs, for example, the Nikon D3S camera is capable of shooting with ISO 102400
