What is ISO and how to configure it

ISO value is one of the most important parameters when shooting, along with such values ​​as excerpts, aperture and white balance. ISO is often referred to as ISO sensitivity, ISO level, or simply photosensitivity matrix or film.

Poster for the article. What is ISO?

Poster for the article. What is ISO?


Still, what is ISO in the settings of the camera?

ISO Is a parameter indicating the level sensitivity to light of its light-picking element (matrices or films). Basically indicate the limits of ISO for cameras (cameras). Although, the same parameter can be found not only on the camera, but, for example, on the flash. For flash, a guide number is usually indicated when using one of the ISO values ​​of 100, or 200. ISO sensitivity indicated in special units of the ISO system. The ISO numeric expression itself can accept any integer expression from 1 to infinity. For example, on my flash SB-900 you can set the ISO from 1 (unit) to 12,500, and on my camera Nikon D40 You can set the ISO value from 200 to 1.600.


Less is better!

The higher the ISO value, the more photosensitive the matrix. It is very important to understand that the higher the ISO value, the less time it takes for the matrix or film to scan the image from the lens. For clarity, I’ll give an example: we shoot in the evening, there is little light, the camera is set to ISO 100, while the camera in the aperture priority (or in any other mode) shows that the picture will be taken with shutter speed 1 / 20s. It is very long excerpt, and at the same time we can get a blurry frame. Because, to reduce shutter speed need to increase ISO. For example, we increased the ISO to 800, while doing so excerpt decrease by 8 times and become 1 / 160s (one hundred and sixtieth seconds). If it weren’t for noise, then one could always shoot at high ISO and never worry about exposure; due to noise, you need to lower ISO and increase exposure and in addition worry about not getting a blurry shot.


Raise, close, reduce!

Parameters excerpts, aperture values ​​and ISO are interchangeable. The amount of light needed for the camera to build the image can be the same for different three values excerpts, aperture and ISO. So, at values ​​of 1 / 60s, F2.8, ISO 100, the camera will receive as much light as at values ​​of 1 / 30s, F2.8, ISO 50 or 1 / 60s, F5.6, ISO 400. In order to compensate raising ISO, you need to close the aperture or reduce shutter speed. The opposite is also true. You can increase shutter speed, open aperture and lower ISO.


ISO affects noise

In fact, the ISO value is also responsible for the appearance of noise in the photo.. Noise is a parasitic distortion in a photograph. Usually they call it that - noise, grain, etc. The higher the ISO, the greater the noise.. And the lower the ISO, the less noise will be. To get the best possible high-quality photo from the camera, you need to shoot at the highest permissible low ISO. Very often it is ISO 200, 100, 50, sometimes they can be designated as Lo1.

Noise difference at different ISO values

Noise difference at different ISO values


Super high and super low ISO

Many cameras have extended ISO range - usually this is software wrapping ISO, and they are designated as Hi1, Hi2, etc. For example, for a camera Nikon D200 HI1 is equivalent to ISO 3200 and on camera Nikon D90 HI1 is equivalent to the value of ISO 6400. Always remember that when shooting at such advanced ISO values ​​there will almost always be a very strong picture noise effect. I strongly recommend not shooting in the extended upper ISO range on any cameras. Also, the range can expand in a smaller direction, so the camera Nikon D90, D300, D700 matter 1, 0.3, 0.7 as equivalents for ISO 100, 160, 130. What is the benefit of expanding to a low ISO range, see my ISO article lo1. Some cameras, in fact, do not have a hardware implementation of ISO, I made this conclusion after ISO experiment.

Noise at different ISO. Example 1 to 1 increase

Noise at different ISO. Example 1 to 1 increase


With which ISO to choose a camera?

When choosing a camera, always look at the minimum and maximum ISO values, and also remember that in 90% of cases you do not have to shoot at extremely high ISOs, since often they simply can not ensure normal image quality. Therefore, professional photographers have ISO working concept. By working ISO is meant the maximum ISO value at which the camera can give an acceptable result. The trick is that unlike the diaphragm and excerpts, which on all cameras give completely the same values, the same ISO on different cameras can give different noise values. Therefore, in one camera, the working ISO will be 800, and in the other, the working ISO will be 3200. For example, on the camera Nikon D700 images of acceptable quality can be obtained at ISO 3200, while at Nikon D200 in ISO 3200 (Hi1) mode, it’s already not a photograph, but complete nonsense. The difference in ISO noise is very strongly felt on digital soap dishes, where digital noise is often very visible already on ISO 400, but at the same time, ISO 400 is quite operational on SLR cameras.


What affects noise at high ISO?

The noise level at high ISO is very much affected matrix size camera. The larger the matrix, the less noise. Given that the matrix is ​​very small in compact cameras, it produces a huge noise level. The explanation can be very simple at the pixel size. The large matrix has large pixels that can absorb a lot more light and thus make a strong electrical signal. It is logical that 12MP with soap dishes and 12MP with Nikon D3s will produce different noise levels at high ISO. More information in my article. matrix size has the meaning.


How is ISO measured?

ISO as well as shutter speed and aperture accepted count in the footstepseg ISO 100, ISO 200, ISO 400, etc. The difference between ISO 800 and ISO 400 is exactly two times or one stop, and between ISO 100 and ISO 1600 exactly 16 times, or 4 stops. It's too bad that cameras generally only allow ISO changes by stop value. So, for Nikon D40 it is possible to manually set ISO only 200, 400, 800, 1600, HI1, and you cannot set an intermediate value such as ISO 250, 320, 500, etc. On more advanced cameras, you can set intermediate values, but still fine ISO control is practically not in any cell. The most interesting thing is that in the automatic ISO mode, the ISO sensitivity can take on any values, such as 110, 230, 1400, etc.


Auto ISO

On almost all cameras available auto ISO. This means that the camera itself will select the optimal ISO value. Auto ISO It is very convenient when shooting with poor lighting, when using it, the camera can squeeze the maximum quality. Basically, when using auto ISO, The maximum shutter speed and maximum ISO value must be indicated. Some cameras adjust the ISO to the focal length of the lens to prevent blur when shooting with your hands. Who cares, you can read how the function of automatic control of ISO sensitivity works on modern Nikon central control centers.


Auto ISO Example

We decided to photograph the cat at home in the dim light of the lamp. We have a 60mm lens, to avoid hand shake, you need to shoot at a shutter speed no longer than 1/60, so we set the maximum shutter speed to 1/60 in the automatic ISO settings, as well as the maximum allowable ISO 800 in order to get the maximum picture quality. When photographing, the camera will try to lower the ISO, and adjust the shutter speed. If the shutter speed is shorter than 1/60 and the ISO is less than the minimum, the camera will automatically extend the shutter speed and lower the ISO and will do so until it hits the preset limit of 1/60 second, while we get the maximum allowable shutter speed and the lowest possible ISO for photographing a cat. If there is enough light, the camera will set ISO 100 (or any minimum acceptable) and any desired shutter speed no longer than 1/60. If the light is catastrophically small, then the camera will set the maximum possible ISO and forcibly increase the shutter speed for the correct exposure. Generally, I I strongly recommend experimenting with auto ISO in aperture priority modesince the operation of automatic ISO is quite specific.


Little trick

When using automatic ISO and flash, it is better to turn off the auto ISO, since very often the camera goes crazy and where you can really lower the ISO, the camera sets the maximum specified and takes a picture with flash. Anyway, if there is a flash, then you can safely use the lowest available ISO.


Another little trick

On a number of DSLR cameras in the auto ISO mode, you can set the maximum ISO in the menu, as well as the minimum. Sometimes, to set the minimum ISO, you just need to set the desired ISO value with the selector, for example, 800. And then, with the maximum specified ISO 1600, you get a working range of ISO 800-1600 at which the camera will work - a very, very useful thing.


Golden ISO Rule

Always remember the golden rule - you need to shoot at the lowest possible ISO. As soon as there is an opportunity to lower the ISO - do it. Raise the ISO only when needed, such as when the shutter speed at low ISO is too slow for normal handheld shooting. To lower the ISO as low as possible - open the aperture as much as possible. If there is a flash, do not use high ISO. Although, sometimes with the flash, you can shoot at high ISO (details here).


 Conclusions

Value ISO directly responsible for photosensitivity and noise level. The higher the ISO, the greater the noise and the worse the photo. Lower ISO - the better the photo, but the longer the shutter speed.


 Have a question? You can ask in the comments. Thanks for attention. Arkady Shapoval.

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Comments: 149, on the topic: What is ISO and how to configure it

  • Maksim

    I just didn’t mean Lo. Here I have an ISO from 100 to 3200 on my camera. It is advised to shoot at 200, since they claim that 100 is already a wrap. Nikon V1 device, if that.

    • Jury

      There are cameras on which ISO 100 is Lo1, but there are also those in which ISO 100 is fair, that is, hardware, and they do not make any “fakes” or drops in dynamic range. For example, Nikon D5100 does not have ISO 200 base, but just ISO 100, it is not an extension of ISO 200.

  • Great Super Photographer

    Writes TS correctly. Helped me to figure it out a bit. I have 6400 the largest. In general, it is not clear why it is. I agree with Maxim - 200 is good. Already comparing with 400, it can be seen that there is more noise by 400 with an increase in the photo. A 64 with flash is just fine.

    Thanks TS.

  • […] Not so long ago I didn’t think too much about ISO (lightness). I will not go into details at once. […]

  • Sergei

    Hello.
    Tell me why, then, do big iso on cameras, if you can’t shoot them qualitatively anyway, it will not work, but there will only be noise? Isn’t it easier to put the maximum iso at the camera right at the factory at which the quality will be acceptable on this camera.
    Thank you.

    • grandfather Fedor

      Different photographers have different goals. Someone captures still lifes indoors under the light of three flashes, where in a watermelon each bone can be distinguished from an arc. And someone is fixing the transfer of drugs at a distance of one hundred meters in a semi-gloomy alley without the ability to use a lighting device. So the second photographer does not need smooth skin on the faces of the models.

    • Dasha

      Because the camera is not always used to create aesthetically beautiful photographs. There are photographers working in hot spots, with crime, etc. And it is important for them not to bring beauty to their pictures, but to capture what is happening. And sometimes this very thing is not covered by the studio softbox. Therefore, to take at least some kind of picture with virtually no lighting, you need to lift the ISO.

  • Lion0608

    By the way, I wanted to ask the author of the article (from his experience, or from communication with colleagues). What to do if everything is “against” quality. The illumination is low, as an example - in winter, freestylers often jump in already complete darkness (you need to increase the ISO), while the movement is fast (sports, children) and the shutter speed should be small (the opposite of the goal of increasing the shutter speed in low light), and you want the camera focused nicely on the subject. And even the most powerful flash can “miss” an athlete who is 300 meters away. And the quality of the picture, for example, is important (for some kind of advertising brochure, and not just “on air.”) Will the quality of the picture still fall? Those. literally "shoot". But this is quite difficult, because here we have a computer with a monitor at hand. Is it possible to carry a laptop or tablet with you everywhere? Or do a trial “session” in advance in conditions close to combat?

  • Novel

    Good day. On Sony's camera, the alpha alpha 7s reaches up to 409600. Does that mean bad?

    • Maugli

      It's horrible! What do they allow themselves there in Sony? =)
      PS: a cool camera that can shoot well in low light.

  • Eugene

    Dear Radozhiva, the photographic system of the camera belongs to iconic systems, i.e. perceiving the whole image at once, without cutting it into columns and lines. Therefore, your expression “the matrix SCAN the image from the lens” is unknown.
    Sorry for my "five kopecks", but the truth is above all. Best regards to all forkm readers and to you personally.

    • Alex

      Eugene, you are right only in this part - that is, indeed, the Matrix perceives an object from the lens immediately and in its entirety. That is, all pixels are simultaneously illuminated by the subject. But we must not forget that in the future, the electronics reads information from each pixel sequentially, that is, it really scans the sum of the signals from the Matrix and starts up this entire array of information in the processing and storage chain, preserving the sequence and targeting of the scan. Therefore, talking about image scanning is, in principle, possible. Indeed, for the same reason, the image is delayed on the display if the camera moves. The human eye, along with its brain, incidentally, processes an object faster in motion than a digital camera, mind you. But this is probably for now. The technique is improving and will ever catch up with the ability of the brain. It seems so to me. Alex

  • Maxim Stoyalov

    Good article.

  • Victor

    Here is some more useful info about ISO
    http://www.bestnewart.ru/about/lessons/cho_takoe_iso.html

  • Victor

    Very non-standard about ISO http://www.bestnewart.ru/about/lessons/cho_takoe_iso.html

    • Arkady Shapoval

      And what is non-standard?

      • Ivan

        Apparently, the author could not do such a simple topic.

  • Michael

    I noticed such an interesting feature on the d80 that in good light, and a slight increase in ISO to 200-400. The frame looks sharper. The color is saturated with colors. A slight noble noise appears. Of course, the ISO 800 does not look fun.

  • Alex

    The article is great and many thanks to Arkady and for his patience and understanding of all the calls to him from all members of the forum. If only there would be more people like that, life on many issues would become easier and more interesting here. Who is eager to delve deeper and in more detail into the nature of ISO, and generally dive into the depths of Sensitometry. then read the materials on Wikipedia. Boot in full. Good luck to all. Alex

  • Best Photographer

    Just take this app and read from cover to cover. Everything is painted in an accessible language with many examples. And you are no longer looking for such stupid questions. Do not spare these shitty 99r. Because it's really worth it.

    https://play.google.com/store/apps/details?id=com.mirbor.forphotographers

  • Peter Sh.

    Since I shoot in large part at the highest ISO, I constantly look for ways to make me suffer less.
    Found some interesting points.
    For example, shots at the same ISO and close shutter speeds can produce dramatically different image quality results. The difference is only in the light.

    Here are two shots.
    On this I closed the curtains on the windows in the morning. The room was relatively dark.

    ISO-24800, RAW from the camera, no post-processing, noise reduction off:

  • Peter Sh.

    And here is a shot from the concert hall with dim light.
    Pay attention to wild noise compared to the previous shot.
    The bee on the afterburner is generally all pockmarked, in color pixels.

    Same camera, IS0-6400, + 1EV in post-processing, noise reduction off:

  • Dima Volgograd

    Tell me, please, how to set ISO Lo1 in Nikon d70?

    • Michael

      It seems in any way. And it’s best to ask this question the instructions of the camera)))

  • Dmitriy

    Refresh the article.
    Firstly, the amount of noise does not depend on ISO, but on the operation of automation in P, A, S modes.
    Secondly, for a long time there are cameras that are tolerant of various ISOs (fuji x-t1, sony a6300, etc.). The picture on them with iso 200 is no different from the picture on iso 3200 + 4Ev.
    So to say that high iso-bad, low-good, at least for 4 years already is not true.

    • Valery A.

      This is a discovery. Does Nikon have "tolerant" ones?

      • Dmitriy

        I don’t know about Nikon, threw off the link, you can search for the camera you are interested in

    • Valentine

      Dmitry, you have a mistake, not an article. Firstly, there are techniques for real measurement of noise, and so far there are no new cameras that produced comparable values ​​to iso 3200 at iso 200 in nature. Finally, there are sites where you can compare the noises of different new cameras in different modes - with and without noise reduction. Where did you get this information about an excellent picture on high iso?

      • Oleg

        Recently, there are a lot of articles on the topic that even with the squelch turned off, the camera continues to programmatically suppress noise. And to some extent, raw RAW is no longer the source file, as manufacturers go to their marketing tricks. The picture is smooth, clean, but the detail is seriously affected. So it's too early to talk about victory over high ISO. Even if you look at the network reviews of the cameras you listed, then the ISO-3200 limit for them and of course 3200 is by no means 200

        • Dmitriy

          I only dispute the statement that high ISOs are always bad, and we should strive to photograph at low ones. on a sunny day, of course, ISO 3200 will not add quality to the picture, but if we are talking about night photos, take a photo with ISO 3200 and ISO 200, in the second photo in the same light room, increase the exposure by 4 stops and understand what I'm talking about. for example, for Canon 6D, the best quality of night shots will be with iso 6400 and higher.

          • Michael

            the best will be with ISO 100 with a tripod

          • Valentine

            Dmitry, not a single normal photographer will recommend you shoot in the dark on iso 200 instead of iso 3200, and then programmatically pull this in the editor. Why did you decide that you should do this? When they say that shooting at lower ISOs is preferable, this does not mean that the frame should be underexposed. Your task is to think about how to make ISO smaller and the frame correctly exposed.
            You can take into account the following: the mechanism for increasing iso in the camera is associated with the operation of the signal amplifier, and the clarification mechanism in the editor with software brightness shift. Moreover, for the editor, the bit depth of the source file is critical. ISO-HI modes in cameras are the same software lighting. But in non-HI modes with ISO, not everything is clear. Until a certain point, an ISO camera amplifier can give a better result than clarification in the editor. But after some value (for each camera, its own), it turns out that shooting at a lower ISO and lightening in the editor gives a slightly better result.

            • Dmitriy

              I’m just saying that you shouldn’t take pictures, but you should switch to high ISO. in fact, we always have a time limit for exposure, even though shooting with hands even with a tripod. therefore, I propose to compare photos with ISO 200 and ISO 3200 with the same exposure. each camera has its own optimal iso for night photography, it needs to be found experimentally, for sony a7s this is for example iso 3700. and the article says that high is-evil, go low, so I propose to fix it, since this not true

              • Valentine

                Dmitry, this specific article does not say that you need to shoot at low ISO and pull photos. There is a link to the article Experiment with ISO, but this is not a call to something, but only a demonstration of the result of the experiment.
                The assertion that if possible it is necessary to shoot at a lower ISO value, in my opinion, few people can raise doubts, since I already know that the closer the ISO to the base, the better the picture will be, all other things being equal.
                And finally, when shooting at high ISOs, you still need to think about how to reduce them. In addition to ISO, other parameters influence the exposure and you should always look for a compromise between them before raising the ISO. There are also many ways how to achieve the desired result without raising the ISO. I’ll always think three times how to frame at a lower ISO with normal exposure before I turn the dial towards increasing it.

        • Valentine

          Oleg, we never see you writing raw RAW at all (it turns out raw raw, but the essence is clear). In any camera, from any manufacturer, data generated by a certain algorithm is recorded in a RAW file. And this very algorithm can be quite complex, significantly affecting the image. Fuji, in my opinion, does a lot to make the images immediately from the camera (in RAW / not in RAW) look better than you could modify it somewhere (their matrices are geared specifically for further refinement by the camera program, and not vice versa when programs only eliminate matrix jambs). Is it bad? I do not think so. If the manufacturer knows in advance that the image displayed by the sensor has weaknesses that cannot be eliminated later by any other methods and immediately tries to correct them in the best way, then why not.

  • Glory

    Everything is very affordable, thanks

  • Berder

    Please recommend which semi-professional Nikon cameras have high working ISOs, suitable for working with a telephoto lens with a focal length of 600 mm in low light (cloudy weather, evening, morning, forest)? (I'm going to buy a second camera and can not decide)

    • Arkady Shapoval

      Write what you already have.

      • Berder

        There is d80

        • BB

          D7100 / 7200/7500, if you want a crop
          D600 / 610/750/850… - for your pocket.
          Comparing 600/610 and 750, the latter is slightly better than AF.
          The crop will have more EGF (i.e., with the FR 600 you will have an EGF of 900mm), but the requirements for short shutter speeds at the long end are also higher, while the working ISO is lower than that of the FF.
          On the other hand, you can always make a crop from FF (with the loss of "permission", of course), but vice versa (get FF from a crop) - nothing.
          PS this is if you do not plan to change the system.

  • Vladimir

    What is native iso and how to use it when shooting on Nikon d90?

  • Alexey

    Good afternoon.
    I would clarify some points in the conclusion “ISO value is directly responsible for light sensitivity and noise level. The higher the ISO, the more noise and the worse the photo. ”
    Here is why.
    1. The light sensitivity of the matrix is ​​unchanged, it is determined by the manufacturing technology and in most cases coincides with the minimum base (for example, ISO 100). All other values ​​are hardware gain (in some models - also lowering) of the light signal, with the goal of compensating for the lack of light entering the matrix. Changing the ISO only changes the brightness of the picture, but not the exposure (the number of photons received by the matrix). The latter is determined only by shutter speed and aperture.
    2. The noise level is influenced by many parameters - exposure, nature of light, matrix manufacturing technology, its size, pixel coarseness, residual charge level in them, matrix temperature, etc. The matrix temperature rises as the light signal increases (ISO increases) and this leads to additional noise. But the root cause is again a lack of light (underexposure), which the camera compensates for by raising the ISO. Thus, the “underexposure” of the frame is “responsible” for the noise level, and the increase in ISO is only an indicator of the brightness gain to an acceptable level. You can carry out a test similar to the one on the DPreview website: shoot 2 underexposed frames taken at the same aperture, shutter speed and light source: one with 1 stop underexposure at ISO 3200, the second with 5 stops underexposure at ISO 200. Then adjust the brightness of both frames in the converter to the same value. The second final frame will be completely destroyed by noise and color distortion, the first one shot at high ISO will be acceptable.
    3. It is also necessary to say about such an important indicator as the dynamic range of the matrix - DD (how many stops a frame can transmit). And it is here that raising the ISO leads to a serious narrowing of this range: from 11-12 stops at a base ISO of 100 to only 8 at an ISO of about 3200.Thus, at high ISO, the quality of the frame deteriorates significantly due to the impossibility of transmitting the entire luminance range of the scene.
    In this regard, I would summarize as follows:
    - The light sensitivity of the matrix is ​​determined, in particular, by the base ISO value, as well as by a number of other above-mentioned parameters.
    - The dynamic range of the frame narrows with increasing ISO.
    - Exposure directly affects the noise level. The more underexposed the frame, the more you need to amplify the signal (i.e., raise the ISO), the higher the sensor temperature, the higher the noise.
    But in general, as the masterpieces of world photography show, the coolness of the photo with the noise level and the width of the DD is not connected at all. But that's another topic :)

    • Arkady Shapoval

      Thank you

      • Alexey

        Thank you. One of the best technology sites.

    • Michael

      For a beginner and without technical education - hefty cool. Is that insert into the body of the article

      • Alexey

        Mikhail, in fact, everything is simple - the technical quality of the photo largely depends on the amount of light entering through the aperture at a given time. And the ISO adjustment stretches, if necessary, the brightness of the picture to the desired one. And the less you need to "pull", the better. So - “let there be light!”.

    • Alexey

      Hello, namesake :)
      Check out my notes over there, scroll down to “A little bit about how the camera changes the ISO value” radojuva.com/2012/02/iso-boost-detect/

  • Vladimir

    And what is “narrative (opposite)
    ISO ”and how can it help you get a quality image?

    • Michael

      Where did you find it?

    • Rodion

      Maybe “native”? Native - “what the matrix gives”, ie with the amplification factor of the electronic strapping x1. It seems like it's usually 100. Some have 200.

      • Arkady Shapoval

        Panas has 160, some 125 (D1x), some new ones - 64. Some cameras have double (200 and 800). The question is probably about the fact that there is a software ISO, like Nikon / Canon for ISO 50 (ISO LO) for some cameras. It is usually called basic.

  • Fedor

    You talked about how to use the ISO parameter, but you did not tell what the physical meaning of this parameter is. For example, when recording in RAW format, this parameter is not reflected in any way. It is only recorded as a shooting condition. And it is used by viewers or editors to recalculate the brightness values ​​recorded in the RAW file in the direction of increasing the brightness. Hence the effect of raising the noise level at high ISO values.
    Knowing this, when shooting on a bright sunny day, you can deliberately increase the sensitivity value from the lowest possible, for example, ISO 100 to ISO 200 (naturally, the amount of light that hits the matrix should be proportionally halved). This will give us one stop of headroom to correct in the editor for overexposures that often occur in bright sun.

    • Aleksey68

      reflected. the gains of the PGA facing the ADC are varied. and not only them. I wrote about this earlier.

    • Arkady Shapoval

      Unfortunately, it is not. Moreover, this does not apply to this topic.

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