What is iso in a digital camera? ISO is one of the three main pillars of photography. The other two important pillars are shutter speed and aperture size. ISO will have a huge impact on your images. But what effect does the amount and sensitivity of your camera ISO have on the final image? In this article, we will examine this concept, introduce it and how it affects photos. People who are new to photography are familiar with this concept at the end of the article and are prepared to use it to capture the best images.
What is ISO?
First we have to introduce ISO. Simply put, ISO is one of the camera settings that makes your photos light or dark. As the ISO value increases, your images become brighter. Because of this, ISO can help you shoot in dimly lit and relatively dark environments, or help you choose and adjust your aperture size and shutter speed.
However, increasing the ISO is not without its drawbacks and has consequences. Photos taken with very high ISO values are not very high quality and have a lot of so-called noise and may be unused. Therefore, turning on a photo using ISO can also have side effects, and we should only use this tool to brighten images when this is not possible using aperture resizing or shutter speed. For example, if speeding up (which increases the brightness of the image) is not possible and blurs the image, you have no choice but to increase the ISO.
What does ISO mean?
ISO actually stands for International Organization for Standardization, meaning International Organization for Standardization. However, the ISO used in cameras does not directly refer to an organization that sets different standards for different products and technologies. In fact, there were two standards called ASA and DIN in photography and videography, which were merged in 1974 and became known as ISO. ISO initially only referred to the sensitivity of films, but later digital camera makers also used the term. Because it works for almost the same purpose, which is to keep the brightness level in the photos.
Common ISO values
Each camera supports a specific range of ISO values, sometimes called ISO speeds. Therefore, you can only use the values supported by your camera. The most common set includes the following:
ISO 100 (low ISO)
ISO 6400 (high ISO)
The choice of these figures and the relationship between them is very simple. When the ISO number is doubled, you are actually doubling the brightness of the image; Therefore, an image with ISO 400 is twice as bright as an image with ISO 200.
What is the basic ISO?
The lowest ISO value of a camera is known as the base ISO. This value is very important, because this value determines the ability to take the highest quality photos on your camera. In fact, the lowest ISO value would mean the lowest Noise and light and color flaws in the image. Therefore, the lower the value, the higher the quality of your image. This is why basic ISO is so important. The base ISO was 200 on most older DSLRs, but some of today’s more modern cameras also support ISO 100. However, remember to use the same amount of basic ISO as much as possible to get the most out of your images. However, this is not always possible. Especially when the ambient light is not enough, you will have to increase the ISO value of the camera.
Some cameras have extra HI and LO values in the range of their normal ISO values. Remember not to use these features. Because these values are not real and only simulate and reduce the quality of your images.
View Noise at high and low ISO values
As mentioned earlier, increasing the ISO value reduces the quality of your image and adds to the noise in the image. The following images were taken in similar conditions and with different ISOs. With a little care, you will clearly notice the difference in their quality. Pay attention to the size of the Noise and the spots created in the photo.
The difference is quite clear: a photo taken with ISO 3200 has a much higher Noise than an ISO 200. In the photo on the left, we have tried to provide the necessary exposure by increasing the shutter speed. This is why you should avoid increasing the ISO value as much as possible.
How to change the ISO value?
How to change the ISO value depends on your digital camera. But in general, there are a few common ways to do this:
- To get started, select one of the camera modes that lets you adjust the ISO manually. So you have to choose one of the Manual, Shutter Priority, Aperture Priority or Program modes. We recommend that you use either Manual mode or Aperture Priority.
- For beginner or mirrorless DSLRs, you should probably open the camera menu (perhaps the Quick Menu section) and find the ISO there. Then enter the desired value or set it to automatic.
- On more professional cameras, there may be a dedicated button for adjusting the ISO. You can adjust the ISO of your camera by pressing or rotating this button. If you do not see an ISO button on the camera, it is likely that the camera will allow you to assign and adjust a button yourself.
- Some more advanced cameras may also have a dedicated ISO button that allows you to select and adjust different values by rotating it.
However, if you are unsure about the mechanism and method of setting the ISO on your camera, it is best to refer to the manual. However, we recommend that you learn and master the ISO setting method well. Sometimes you need to change this amount quickly and often. Especially when you are planning to shoot in a dimly lit environment without using a flash. So more familiarity with setting it up can help a lot.
What degree of camera ISO should we use?
Many photographers understand the basic concepts of ISO well, but when choosing and shooting, they still do not know what value to choose for the ISO of their cameras. In practice, there is a specific reason for offering a wide range of ISO values in cameras. Each of these values is better suited for specific environmental conditions. In the following, we are going to introduce and explain some of the most common scenarios for setting ISO.
When to use low ISO?
As mentioned before, you should always try to use the minimum ISO value of your camera (base ISO). This is a probable value of ISO 100 or ISO 200. If the ambient light is high and sufficient, you will have no problem doing so, and with the lowest ISO size, you can capture the best image quality with the least noise.
Even in dark and dim environments, you may be able to use low ISO. For example, if your camera is on a tripod or you place it on a table, you can still use low ISO, but instead slow down the shutter speed and use a longer shutter speed. This will make the camera collect more light and make your photo brighter. Since the camera is mounted on a tripod, you will not notice the main threat of long shutter speeds (image shake and blur). But remember, when you use a long shutter, anything that moves in the image may look like a ghost!
Of course, in the photo above, we have added a little joke to the photo. In this photo, we were going to test a long exposure. So we set the ISO to a minimum so that the details remain intact. Instead, we slowed down the shutter speed to 5 seconds. The subject of the photo was fixed in these 5 seconds, but one of our friends appeared in the frame for a short time of these 5 seconds and played the role of a pseudo! Because he was not in the frame for all 5 seconds, his image has disappeared.
When to use high ISO?
Although using low ISO is ideal, there are many cases where you need to use high ISO to capture good photos in the first place. There’s a simple reason for this: to use the low ISO, we need to slow down the shutter speed instead to get the right exposure. It is not possible to use long shutter speeds to photograph moving objects, and we encounter the Motion Blur phenomenon. That is, moving subjects were blurred in the photo (like the previous photo). Two modes are created: either we take a clear photo without Noise, but we lower it with ISO by blurring the subject. Or the subject of our photo is clear, but the photo has more Noise. Therefore, we must choose the right balance between ISO and shutter speed so that the exposure is good and at the same time we do not suffer from Motion Blur. In this situation, we have to increase the ISO value.
We took this photo at a speed of 2,000 m / s with an ISO of 800. Here we needed to take a photo with a fraction of 2,000 m / s to record the bird’s movement in the sky completely and without vibration. In this situation, what would happen if we wanted to use ISO 100? In this case, we had to use a shutter speed of 1.250 m (one friend and fifty) seconds to have a clear image. In this case, there was a lot of shaking and blurring in the photo, because the birds were moving at a high speed and their trajectory was disappearing throughout the photo. In other words, our photo would be destroyed!
All in all, we had to increase the ISO of the photo to have enough light to capture a clear and beautiful photo with fast shutter speed. In similar situations, if we are going to shoot indoors without a flash, it is still better to increase the ISO value so that the photo has enough light and at the same time to avoid additional vibrations caused by slowing down the shutter speed. Likewise, it is not possible to shoot very fast subjects without increasing the shutter speed. Because by increasing the shutter speed (for shooting fast subjects), not enough light enters the lens and we have to solve this problem by increasing the ISO.
Most cameras also have Auto ISO mode, which automatically adjusts the ISO value to fit other variables (shutter speed and aperture size). This mode usually works well in low light environments. The most attractive part of this camera feature is that it allows you to enter the maximum ISO you want. Therefore, if we want to limit the Noise of the image, it is better to set a reasonable ceiling for ISO. In our opinion, ISO 800 to ISO 1600 can be a good choice. The disadvantage of this mode is when shooting in low light environment, and if this amount of ISO is not enough for the brightness of the image, the camera slows down the shutter speed and as a result may cause more shake and blur in your photo. Therefore, it may be best not to be too strict in choosing an ISO ceiling. ISO 3200 and even higher will be required for photography in some situations.
Minimize noise and maximize photo quality
Some photographers think that the only way to get high quality photos is to always use ISO. But this is a misconception. As shown in the example above, sometimes you have no choice but to increase the ISO value of your camera.
You should only use the basic ISO when there is enough light in the environment. Never try to shoot at ISO 100 or 200 in dark environments. On the other hand, if you use fast shutter speeds to capture fast-moving subjects, you still have to increase the ISO to get better exposure. As a general rule of thumb, keep in mind that you must either use ISO or change the shutter speed to adjust the exposure. The setting of these two variables is related to each other, and many times you have to sacrifice one to the other. In line with the previous discussion, keep in mind that in some specific styles of sports photography, you may also need to use a higher ISO.
To improve the quality of photos and maximize it, consider the following four steps:
- Select the aperture size settings so that you can give the right depth to the photo.
- Set the camera’s ISO to the base ISO value (usually 100 or 200) and adjust the shutter speed to suit the exposure. Selecting the automatic mode for shutter speed can also be a good choice.
- If the subject of your photo is blurred and shaken, gradually increase the ISO value until the other image is blurred and shaken.
- If you feel that the ISO size is too high, you can go to the aperture and choose a larger size. As you know, the larger the aperture, the more light enters the lens and the better your exposure. You can also use this method to better manage the ISO size and avoid raising it too high. But keep in mind, this can cost you a portion of your image depth.
As mentioned, shutter speed, aperture size and ISO are the three main sides of the photographic triangle. As a photographer, you should try to strike the right balance between these three elements. Ideally, you can keep everything together well. But as the circumstances become more specific, you may need to revise the settings and balance as you wish.
If you follow the above, you can easily maximize the quality of your photos and get the right balance between Noise, Motion Blur and image depth.
Answers to frequently asked questions about camera ISO
There are many mysteries and frequently asked questions about ISO. In this section, we want to answer some of the most common of these questions.
Is ISO the same as sensor sensitivity?
This is one of the most common questions and concerns about ISO. In many articles published on the Internet, you will find that ISO is the same as sensor sensitivity. While this may help you to imagine that the ISO works “like” the camera sensor, this claim is incorrect and the ISO performance is different. Digital sensors have only one sensitivity and that has nothing to do with ISO. It is safe to say that ISO is a kind of map that tells your digital camera how bright your photo should be.
Is ISO part of the exposure?
No. ISO is not part of the exposure. Shutter speed and aperture size physically help your camera absorb more light. But ISO performance is different and does not work physically. Instead, ISO can be considered a program that makes the captured image brighter. For this reason, photographers do not consider ISO to be part of camera and photo exposure.
Is increasing the image ISO the same as turning on photos with a computer?
This is a very interesting question, but it’s another misconception about ISO cameras. Turning on images on a computer is in many ways similar to raising the ISO, as it also increases image noise. But the main difference between the two methods is that increasing the ISO in the camera can always lead to higher quality photos than increasing the brightness of the photo using a computer. In other words, instead of trying to lighten an ISO 800 captured image with photo editing programs like Lightroom or Photoshop, it is better to use ISO 800 if necessary.
What is the effect of ISO on the photo?
ISO increases or decreases the brightness of your photo. But it also affects the noise level of the images and their dynamic range. At the lowest ISO (or base ISO), your photo has the lowest Noise and the most dynamic range. So you will have the most flexibility when editing photos. As the ISO increases, the Noise levels of the image increase and the dynamic range of the image naturally decreases.
What is the best ISO for shooting in low light environments?
When you shoot in low light, the shutter speed automatically slows down, resulting in a blur or blur. To avoid a problem, you should increase the ISO value to balance the exposure. The amount of ISO should be selected and increased depending on the size of the aperture and the lighting conditions of the environment.
What is the best ISO camera for nature photography?
When shooting landscapes, you should use a tripod and set your camera ISO to the base ISO value (usually ISO 100).