What is ISO on a camera, and why is it so important?

One of your camera’s most crucial settings is ISO. ISO is regarded as one of photography’s three pillars. Shutter speed and aperture are the other two critical parameters. ISO, on the other hand, has a significant influence on the appearance of your photographs.

But, exactly, what does ISO mean on a camera? What effect does ISO have on your photos, and how can you manage it? This is exactly what we’ll find out right now.

What Is ISO On A Camera?

For newbie photographers, ISO is one of the most misunderstood camera settings. If you’re new to photography, you might be wondering what ISO is and what it does. Simply said, ISO adjusts the brightness or darkness of a picture.

When you boost the ISO on your camera, your image becomes brighter over time. This is why ISO is critical for producing crisp images in low-light situations like basements or at night while photographing the Milky Way.

ISO is another important option that works in conjunction with aperture and shutter speed to generate the sharpest photos possible. These three parameters nearly usually function together, and knowing one without knowing the others is almost useless.

Increasing your ISO does more than merely brighten your photos. If you don’t do it correctly, it might really harm your photos. An image with too much ISO will have too much noise in it, making it blurry and useless. Changing the shutter speed or aperture is sometimes a better alternative than increasing ISO. The ISO settings nearly always have a sweet spot, but finding it takes some effort.

What Does ISO Stand For?

The International Organization for Standardization (ISO) is a non-profit organization dedicated to the development of international standards. This doesn’t appear to have anything to do with photography at first glance. But that’s what the abbreviation means.

When two film standards (ASA and DIN) were unified in 1974, ISO became the standard for organization. These standards evolved into ISO, which was initially intended primarily for film sensitivity. Later on, ISO was adopted by digital camera makers so that they could all maintain consistent brightness levels. ISO is now a globally accepted standard. It is the international standard for brightness levels, and all measurements are the same for all camera manufacturers on the planet.

What Are The ISO Values?

ISO values typically range from 100 to 6400. The following are the details:

  • 100
  • 200
  • 400
  • 800
  • 1600
  • 3200
  • 6400

As you can see, the ISO increases by a factor of two with each level. ISO 100 is the lowest level of sensitivity on this scale, while ISO 6400 is the maximum level. When you increase the exposure value from 100 to 200, you effectively double the brightness of the shot. A photo taken with an ISO of 200 will have double the brightness of a shot taken with an ISO of 100.

What Does Base ISO Mean?

The term “base ISO” refers to the lowest ISO setting available on your camera. This is an important option since it provides you with a significant amount of chance to make high-quality photographs while minimizing as much noise as is technologically possible. The base ISO setting ensures that you begin with the most realistic setting possible, letting you to adjust the ISO when higher levels of brightness are required.

The default ISO setting on most current digital cameras and DSLR cameras is 100. As a general rule of thumb, you want to keep your camera’s base ISO as low as possible for the greatest image quality. It is only when you are working in less-than-ideal lighting circumstances that you should consider adjusting your basic ISO setting.

High & Low ISO Settings

If you’ve ever looked into purchasing a new camera, you’ve definitely seen that some models have extended ISO numbers that go well above 6400. These have a negative impact on image quality and should be avoided wherever possible. The only time you would need to utilize an increased ISO setting is if you were photographing in near-total darkness or in complete darkness during the nighttime.

If you want to see how much of a difference high ISO levels make, consider this: a photograph captured at ISO 200 may come out clear and beautiful, but increasing the ISO to 3200 causes it to become grainy and pixelated like the picture on an old television set. If at all possible, avoid boosting ISO unless absolutely required.

How Do I Change My ISO Settings?

Changing your ISO level is frequently dependent on the type of camera you are using. In most cases, you’ll want to switch to manual mode, shutter priority mode, or aperture priority mode to begin with. You must be shooting in a setting that allows you to choose your own ISO speed before you can proceed. Aperture priority or manual are the two greatest modes to be in when photographing.

After that, you’ll need to locate a menu, most likely the fast menu. There will be a section dedicated to ISO standards. Find the value you want to use or set it to “automatic.” That’s all it takes to make a modification to the configuration.

Keep in mind that some of the more costly cameras may come equipped with an ISO button on the camera body. By pressing the dedicated ISO button while spinning one of the setting wheels, the camera will automatically adjust the ISO level. If you have any questions regarding any of this, simply consult the user handbook for your camera.

Which ISO Setting Is Best?

Almost always, the basic ISO setting is the most optimal. This suggests that either ISO 100 or ISO 200 is required. When there is sufficient illumination, there is no reason to deviate from the default ISO setting. If you want to make your image appear brighter, experiment with the other options available. When shooting in strong light, increasing the ISO will result in a noisy image.

This holds true even in low-light situations. When photographing in low light, it is frequently possible to retain the ISO at its lowest level and brighten your photographs by raising the shutter speed instead of increasing the ISO. This is especially true if you’re using a tripod and the camera isn’t moving at all during the shot.

But, let’s speak about turning up the ISO to its maximum possible level for the moment. There is an appropriate time and place for this. One of the most important reasons to raise the ISO on your camera is to combat motion blur. This is common when dealing with moving objects. If you’re attempting to photograph a moving animal, you’ll need a shutter speed that is quite rapid. The downside is that if your shutter speed is too quick and your ISO is too low, your final image will not be sufficiently bright.

For example, a shutter speed of roughly 1/250th of a second is often required when using an ISO level of 100. If you’re trying to capture fast-moving wildlife like birds or cats, this is a touch too sluggish. A shutter speed of around 1/2000th of a second is required to capture a crisp photograph. However, if you shoot at ISO 100, the shot will be excessively dark and fuzzy. To compensate for the short amount of time your shutter is open to capture light, you must increase the ISO setting to around 800 to obtain more brightness.

In other words, when your camera is unable to catch enough light for the shot, you must boost the ISO setting. The good news is that, in most cases, you will not be required to manually adjust the ISO in these circumstances. Almost every contemporary camera includes an automated ISO option, which means that the ISO will be automatically determined based on the brightness of the scene and the shutter speed you choose. Changing your shutter speed from 1/250 to 1/2000, for example, will immediately adjust the ISO setting.

It’s also critical to select a maximum ISO, even while shooting in automatic mode, to avoid overexposure. As long as you keep the highest ISO setting at 800, you can avoid your camera mistakenly producing too much noise in your photographs. It is quite unlikely that you will need to use the camera at a resolution higher than 800.

ISO & Night Photography

Night photography is one of the few situations in which you will be forced to utilize a higher ISO setting. This is due to the fact that everything you’ll be looking at will be pitch black at night. The background is black, your subject is generally dark, and there isn’t likely to be any reliable source of external light to help you out in this situation.

The increased sensitivity to the little amount of light available during a night photography session allows you to use a slower shutter speed while maintaining the same exposure by increasing the ISO setting on your camera.

The key here is to avoid increasing the ISO to an excessive level. Even at night, a high ISO setting can introduce too much noise and grain to your image. When photographing in low light, you must maintain the ISO as low as possible while still being able to capture the scene.

The ISO setting for professional photographers at night is normally anywhere between 1600 and 3200, depending on how much moonlight is available and whether or not there are any other external sources present. Depending on how bright the moon is, you might be able to get away with using ISO 800. Your first few nights out will undoubtedly be a learning experience, so don’t be discouraged if your photos are a bit grainy, a little loud, or maybe a touch too dark on the first few occasions.


ISO is a comprehensive and difficult standard to comprehend. If you’re a newbie, the one thing you need know is that ISO is an international standard for determining brightness. When you boost the ISO on your camera, the brightness of the shot will rise, which might be detrimental if you aren’t familiar with what you’re doing.

You’ll want to keep the ISO at its lowest possible setting, which should be around ISO 100 or ISO 200. Excessive ISO settings should only be employed when absolutely essential. Make sure to learn more about the ISO, aperture, and shutter speed so that you can get the proper brightness in your images. In order to generate high-quality photographs, all three settings must be used in conjunction.



Joseph is a talented photographer and videographer based in the USA, with a thriving career as a freelance creative. Over the past several years, he has had the privilege of working with renowned brands, capturing captivating images and videos. His portfolio encompasses a diverse range of subjects, specializing in fashion, portrait, and lifestyle content creation. From editorial shoots to engaging social media videos, Joseph's versatile skills ensure exceptional visual storytelling in every project. Beyond his professional endeavors, he nurtures a personal passion for travel and nature photography, channeling his deep appreciation for the environment into a commitment to sustainability and environmental causes.

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