Camera ISO Explained for Beginners
Michael • updated July 7, 2022 • 7 min read
Michael • updated July 7, 2022 • 7 min read
The ISO setting is one of the three most important camera settings in photography. It can change the way how your photos look and even how they feel.
Image quality in photography is determined not only by exposure time and aperture but also by the ISO number, which is also part of the Exposure Triangle.
What is the ISO value, and how does it change the pictures you take? As a beginner photographer, it’s good that you’re learning about it. It’s a big step forward. In this article, we explain what ISO is and how you can use it to create better photos.
The name “ISO” refers to International Standard Organization, and it is the standard classification for your camera’s sensor’s light sensitivity.
The camera sensor’s light sensitivity must be adjusted independently depending on the lighting situation. The higher the light sensitivity and consequently the ISO rating for a photo shoot, the lower the lighting conditions are. As a result, the sensor’s sensitivity to light can be compared to that of a human eye.
When the light is turned off in the evening, it takes a while for the eyes to adjust to the new light conditions and recognize things. The ISO number on the camera controls the camera’s response to the light environment.
“International Organization for Standardization” is abbreviated as “ISO.” The ISO of the camera, on the other hand, does not directly refer to this body, which develops technology and research standards.
There were two other standards in place before ISO: ASA and DIN. These were then integrated into the ISO standard in 1974.
Although the ISO standard was created to describe film speed, it was eventually adopted by digital camera manufacturers with the purpose of retaining film-like brightness levels. Since then, this norm has been applied to both photography and videography.
The term “ISO” originally referred to a film’s sensitivity, or its capacity to “collect light.” The ISO value indicates how well a film can capture photos in low light. The higher the ISO, the better. The fast film was referred to as high ISO film because it required a shorter exposure than low ISO film.
Using digital cameras has made life easier. In this case, the ISO value tells us how light-sensitive the image sensor really is. The ISO values can be modified in the settings menu so that they are always in sync with the lighting conditions that exist at the time of capture.
In addition, a lot of digital cameras allow you to set the ISO automatically. The camera will constantly try to choose the best option for itself.
Your “base ISO” is your camera’s lowest native ISO. This is a crucial setting since it allows you to achieve the best image quality while reducing the visibility of noise as much as achievable.
Many modern digital cameras have a base ISO of 100, however, some previous DSLRs and a few modern cameras have a base ISO of 200. As you can see. “base ISO” is the lowest ISO value a camera has to offer.
Ideally, you should take your pictures with the base ISO to get the best image quality. However, this is not always possible, especially in low light conditions.
Time of day and light situation ISO range examples:
As previously said, you should aim to use your camera’s lowest ISO (base ISO). Normally, this means ISO 50 or 100, but if there is a lot of ambient light, you can use a lower ISO to reduce the amount of noise.
When your photos become too dark, gradually increase the ISO value until your image is bright enough. You can still shoot without fear in the ISO range of 400- 800 because graininess appears mainly in the upper range of 800- 1600.
In sports photography, this ISO range is commonly utilized. To keep the subject sharp, you must shoot fast-moving subjects with an extremely quick shutter speed.
With a faster shutter speed, less light reaches the sensor. This is precisely where the ISO range comes in handy. So it can also be used when there is actually enough light, but at the same time, extremely fast shutter speeds are required.
The human eye already detects less light at dusk. On full-frame cameras, very high ISO values allow you to go beyond these boundaries and photograph virtually in the dark (without flash or other light sources).
The sensor is adjusted to a very high ISO (for example, 51200) so that it can still pick up leftover light that is no longer visible to us. Infrared photography is similar.
However, such high ISO numbers should be approached with caution. The grain on your camera display will never look the same as it does on your home screen.
With cheap low-quality lenses, you won’t be able to shoot professional shots in dark settings. ISO will no longer be of assistance. Only a fast lens will allow you to go further with your photography.
Advanced ISO settings are available on some cameras. The ISO values are referred to as “High ISO” and “Low ISO.” These are higher than the camera’s ISO range. The majority of the time, however, these just lighten or darken the photos captured by the camera.
As a result, the image loses quality. We would recommend, that you only use those settings when you know what you are doing.
In fact, we’ve learned that low light needs a high ISO and low light needs a high ISO. This is mostly correct. But the shutter speed and aperture also affect how bright an image is, not just the ISO value. The exposure triangle in the below illustration shows this quickly.
You can make an image brighter in three ways.
As you can see, there are many ways to get a bright picture, which means you can keep the ISO value low. You can use a low ISO value even when it’s dark. For instance, if you put your camera on a tripod or a steady surface.
In this case, you can use a low ISO and make your photo brighter by taking it for a long time, since the tripod will keep the image from moving. You can only use the camera up to a certain shutter speed before the picture gets blurry.
Most current cameras have an ISO of 100 or 200 as a default. This standard value generates very low-noise photographs, therefore it’s preferable to use it as a starting point when adjusting the sensitivity.
One f-stop more or less light corresponds to doubling or halving the ISO value. Like all other exposure parameters, “ISO,” as it’s known among photographers, contains intermediate increments, commonly in thirds. As a result, your camera’s ISO range looks somewhat like this:
100 – 125 – 160 – 200 – 250 – 320 – 400 – 800 – 1600 – 3200 – 6400 – 12.800
The ISO value for 50 is sometimes known as “L” for “low,” as it is a lower, electronically generated value than the camera’s basic ISO.
The “high-ISO range” refers to ISO values above 6400, where image noise has already increased dramatically. For harsh illumination situations, both are usually more of an emergency solution.
You may believe that a high ISO number is an answer to all lighting issues. However, there is a catch. Increasing the ISO level has a drawback: the higher the number, the more likely noise effects will show in the photographs.
At ISO values of 400, in particular, inexpensive compact cameras frequently provide unsatisfactory pictures.
The basic noise of the picture sensors is the source of so-called image noise. The sensitivity of the image sensor is increased by increasing the ISO values. The noise level, on the other hand, rises at the same time.
The greater the value, the more noticeable the noise in the form of color and brightness noise gets on the photographs. These white or colored missing pixels are most noticeable in the photographs’ dark sections.
If your photos have picked up noise, you can use special software to partially repair the problem. After that, you can alter the raw data types with paid tools like Photo Ninja or Neat Image. It will never be feasible to totally remove errors, though. Your camera must be capable of delivering RAW files for this to work.
First of all, let’s start with the basics: the overall exposure of an image is made up of the three factors mentioned above. You have the greatest creative possibilities with the aperture – it regulates the depth of field and bokeh, i.e. decides how much or little of the background you want to show in your pictures.
The exposure time factor (also called shutter speed) is quite self-explanatory: it indicates how long light falls on the sensor. Here, optical differences often only arise at very long exposure times, where blurred or out-of-focus results can occur – the desired effect when photographing flowing water, for example.
Light sensitivity, on the other hand, usually has a negligible effect on the final image look: it is often only adjusted when the desired exposure can no longer be achieved via aperture and exposure time.
A higher ISO value lets more light into the picture and thus enables photography in darker environments – but also causes an increase in image noise.
Most cameras have an Auto ISO setting that usually works well in low light conditions. This setting has the advantage of allowing you to set the maximum ISO value you want to use.
The camera will then not pass that limit. Beginner photographers should set the Maximum ISO to 800, if you have an actual camera model ISO then 1600 is fine.
The disadvantage is that after the camera approaches this ISO level, it will use increasingly slower shutter rates. As a result, there may be more motion blur. So everything is a compromise, and you really should always examine your photographs on the LCD.
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As already described, high ISO values can lead to unwanted noise effects on the images. The lower the ISO setting selected, the clearer the photos will appear as well.
If you choose ISO 50, the noise will not be visible. For this reason, you should be careful when deciding to change ISO values.
By adjusting the aperture and exposure time, you can also regulate the amount of light hitting your image sensor. It’s better to use these options in conjunction with a tripod. Don’t have one at hand?
A wall or other solid surfaces are available almost everywhere. This way you can also counteract unwanted camera shakes.
to popular belief, high ISO values are often not too problematic. Look at it sportingly: if the lighting conditions are so bad that you have a black image on the sensor with “appropriate” exposure time and aperture at ISO 800, screw the film speed rather than the first two factors.
With ISO 3200 you get four times the light yield – and thus a perhaps somewhat noisy image, but at least an image at all.
Most image editing programs already come “from the factory” with one or even several noise reduction functions. However, be careful not to overdo it here. A healthy balance preserves essential details and edges while reducing unpleasant image noise.
Noise has a bad image – understandable in a commercial environment, where the goal is usually to achieve technically perfect images. In creative photography, however, noise can actually be a beautiful stylistic device – just think of the grain in analog film.
In the meantime, many camera sensors still produce noticeable image noise in high-ISO ratios, but in some cases, it actually creates a beautiful look rather than being a nuisance.
ISO and shutter speed are both parts of how bright or dark an image is. We imagine ISO as a slider for exposure. Its main job is to make your photo brighter or darker. Motion blur in photos and capturing fast-moving stuff in photos are mostly about shutter speed.
If you want your photos to be properly exposed, you should also pay attention to the ISO value. You can brighten your images with an increase. However, as the ISO value increases, the image will become noisier. Image quality will deteriorate.
In some cases, there is no other option. An image with some noise is preferable to no image at all. In image processing, you can also reduce noise after the fact. As always, simply take the camera and experiment. That way, you’ll learn when to raise the ISO and when it’s not necessary.
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