What is ISO? The Complete Guide For Beginners

Shutter speed and aperture are the other two pillars of photography, and ISO has a significant impact on your photos. Is there a difference between images taken with and without a high ISO setting? In this article, we’ll cover the basics of ISO and show you how to get the most out of it.

1. What Is ISO?

For the uninitiated, ISO is just a camera setting that controls how bright or dark a picture is going to be. Your photos will become brighter as you increase the ISO setting on your camera. That is why ISO can assist you in taking pictures in low-light situations or be more adaptable when it comes to aperture and shutter speed.

However, there are drawbacks to increasing your ISO. The grain in a photo taken at a high ISO setting is referred to as noise, and the photo may not be usable. As a result, increasing the ISO to make a photo brighter always comes with a cost. If you can’t brighten your photo with a faster shutter speed or a wider aperture, then only increase your ISO (for example, if using a longer shutter speed would cause your subject to be blurry).


1.1 What Is The Meaning Of ISO?

“International Organization for Standardization” (ISO) is the acronym for the organization. Camera ISO, on the other hand, is not a shortened form of the name of the organization that develops industry standards. ISO standards have been referred to as one word “ISO” since the two film standards known as ASA and DIN were combined in 1974 into ISO standards (later revised for both film and digital photography). Digital camera manufacturers adopted ISO in order to maintain film-like brightness levels, despite the fact that it was originally designed to define only film sensitivity.

2. Common ISO Values

Every camera has a different range of ISO values (sometimes called ISO speeds) that you can use. A common set is as follows:

ISO 100 (low ISO)
ISO 200
ISO 400
ISO 800
ISO 1600
ISO 3200
ISO 6400 (high ISO)

Quite simply, when you double your ISO speed, you are doubling the brightness of the photo. So, a photo at ISO 400 will be twice brighter than ISO 200, which will be twice brighter than ISO 100.

3. What Is Base ISO?

“Base ISO” refers to your camera’s native ISO setting that is the lowest possible. This is a critical setting, as it allows you to achieve the best possible image quality while also reducing the amount of noise that can be seen. Compared to most modern digital cameras, which have a base ISO of 100, older DSLRs and some modern cameras like the Fuji X-T2 have a higher default ISO of 200. To achieve the best possible image quality, you should always use the camera’s default ISO setting. Even in low-light situations, it’s not always possible to use a bright lamp.

Note for the record:

ISO values can be expanded beyond the camera’s native range by using the “HI” and “LO” buttons on some models. They’re simulated, though, so your image quality will suffer as a result. They should be avoided at all costs.

4. Low vs High ISO Noise Visibility

Take a look at the comparison below to see two photos taken at two different ISO settings. See how much noise (such as blurry or washed-out colors) is in the images.

The ISO 3200 image has significantly more noise than the ISO 200 image (which I brightened with a long shutter speed instead). As a result, unless circumstances dictate otherwise, you should avoid using high ISO settings.

5. How To Change ISO

For example, some cameras allow you to adjust the ISO, while others do not. Changing the ISO setting can be accomplished in a variety of ways, as follows:

+ To begin, select an ISO setting that you control. Change the camera’s settings from Auto to Manual, Shutter Priority, Aperture Priority, or Program (we tend to prefer Aperture Priority or Manual).

+ If you’re using an entry-level DSLR or mirrorless camera, you’ll likely have to go into the menu system and locate the ISO setting. You can either choose a specific value or leave it on Auto.

+ An “ISO” button may be available on higher-end cameras. To change the ISO, hold down the button and spin one of the dials. Even if your camera does not have a “ISO” button, you may be able to program one to perform this function.

+ The ISO wheel on some cameras is pre-marked with the various ISO settings. As a result, things are made even simpler.

If you’re still unsure, refer to your camera’s manual. However, knowing how to quickly change your ISO setting is important because you’ll be doing it a lot if you’re shooting in low light without a tripod or a flash.

6. What Camera ISO Should You Use?

The fundamentals of ISO are well understood by many photographers, but they are unsure of which ISO setting to use when out in the field. Different situations necessitate using different ISO settings, which is why your camera has such a wide range of ISO options. We’ll go over some of the more typical situations you might run into down below.

6.1 When To Use Low ISO

As previously stated, whenever possible, use your camera’s lowest ISO (base ISO), which is typically ISO 100 or 200. If there is sufficient light, you can use a low ISO to reduce the amount of noise that appears on the image.

You may be able to use a low ISO even in dim or dark conditions. For instance, if your camera is mounted on a tripod or is resting motionless on a table, you can get the best results. You won’t introduce camera shake if you use a low ISO and a long shutter speed to brighten your photo instead. However, bear in mind that anything that is moving will appear as a ghost if you use a long shutter speed.

Really? Of course not! My long exposure test’s subject was none other than my adorable nephew. To keep the details, I used the lowest ISO setting on the camera and a five-second shutter speed to get a decent exposure. My nephew remained perfectly still as my friend briefly introduced the ghost to him while my nephew sat perfectly still as well.

6.2 When To Use High ISO

Even though using low ISOs is preferable, there will be times when using a high ISO is necessary to begin with. As a result of having to contend with blur when taking photos in fast-moving situations, you’ll often have to choose between taking sharp photos with high ISO or blurry photos with low ISO. Observe the following image:

I captured these Barn Owl at 1/2000th of a second and ISO 800. When the birds were in flight, my camera needed 1/2000th of a second to capture them in full motion. Would the results have been different if I had used ISO 100 instead of 200? An image this vibrant would have required a shutter speed of 1/250 of a second. Because the birds were moving so quickly, the photo would have had a lot of unwanted motion blur. For better or worse, my presence in the photograph would have muddled the composition.

This means that if your camera cannot capture a clear, bright photo with the light it has, you should raise the ISO setting. In order to avoid introducing blur into my photos taken with a handheld camera inside without the use of a flash, I always increase the ISO on my camera. Increasing your ISO is often necessary when photographing fast-moving subjects, such as the bird in the image above.

Auto ISO is a common camera setting that excels in low-light situations. Because you specify the maximum ISO setting, the camera will not go above it. This is a wonderful feature. In order to reduce noise in a photograph, I usually use an ISO setting of 800, 1600, or 3200. Unfortunately, if the camera’s ISO reaches these preset limits, it will start using longer shutter speeds, resulting in more motion blur. Everything is based on a cost-benefit analysis!

7.Minimizing Noise And Maximizing Image Quality

Using Base ISO 100 percent of the time is recommended by some photographers as the best strategy for capturing high-quality images. However, as has been shown above, this is simply not the case. When shooting in low light, you may be forced to use a higher ISO.

Base ISO should only be used in low-light situations. Avoid using ISO 100 in low-light situations because your photos will be far too dark. The same is true if you’re trying to capture action with a fast shutter speed in a dark environment (since you strictly limit the amount of time your camera sensor is able to capture light). As a result, if you’re shooting sports or action, a high ISO may be your only option.

The following are the four steps to follow in order to achieve the best possible image quality:

+ Decide on the depth of field you desire and adjust the aperture to achieve it.

+ Use a shutter speed that produces a proper exposure while keeping your ISO at its default setting.

+ To eliminate motion blur from your image, increase your ISO and use a faster shutter speed.

+ You can use a wider aperture even if it means sacrificing some of your desired depth of field, if your ISO is too high and you still have the option to use one.

It’s as simple as that! You’ll always get the best picture quality if you follow these simple instructions. You’ll be able to strike the perfect harmony between background noise, motion blur, and focus.

8. Common ISO Myths And Misconceptions

There are numerous myths about ISO, some of which are fairly common. So that you are not misled about this topic in the future, we will quickly address some of those concerns here in this section.

Is ISO “Sensor Sensitivity”?

This is the most common myth related to ISO. It is something you will see all over the web (and in print). However, although it may help you to think of ISO as “acting like” camera sensor sensitivity, that’s not what it actually does. Instead, digital sensors only have a single sensitivity, regardless of your ISO. It is more accurate to say that ISO is like a mapping to tell your camera how bright the output photo should be, given a particular input exposure.

Is ISO Part of Exposure?

Exposure has nothing to do with ISO. Shutter speed and Aperture increase the amount of light that is captured by your camera, resulting in a brighter photo. Instead of doing that, ISO simply brightens the image you’ve already taken. Because of this, photographers do not include it in their exposure calculations.

Is Raising ISO Just Like Brightening Your Photo on a Computer?

This is a well-intentioned question, but it is based on a misunderstanding. Increasing the brightness of a photo on your computer can have many of the same effects as increasing the ISO because it makes noise more obvious (and it leads to a brighter image). There is, however, a fundamental difference between brightening a photo on your computer versus increasing the ISO on your camera. If you must brighten an ISO 100 photo in post-processing software like Lightroom, use ISO 800 instead of the lower-quality setting.

How Does ISO Affect a Photo?

The ISO setting affects both the grain/noise level and the dynamic range of a photograph. Your images will have the least noise and the highest dynamic range when shot at the lowest (base) ISO setting. This gives you the most latitude when it comes to post-processing. With an increase in ISO, you’ll notice a rise in noise and a drop in dynamic range.

What is the Best ISO Setting for Low-Light?

Because shutter speeds slow down in low light, you may end up with camera shake or motion blur. To avoid these problems, try using an ISO setting of 1600 or higher. You may need to increase ISO even further if your aperture or lighting conditions require it.

What is the Best ISO Setting for Landscape Photography?

Landscape photography necessitates the use of a tripod and a low ISO setting, such as 100.

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