What Is ISO? Understanding ISO Settings For Beginners

Using a camera can be complicated for beginners, but it doesn’t have to be. If you can only understand how a camera works and the features to look for in a camera to get a quality picture, then you’re on your way to becoming a pro.

One of the essential features you should look out for in a camera is the ISO. Being one of the three necessary things you have to set up on your camera, it would, thus, be prudent to know a little about it.


What Is ISO?

What Is ISO? Understanding ISO Settings


ISO is one of the key factors that determine the quality of your photos in terms of lighting. Usually measured in numbers. And if the number of the ISO is low, the lower the film sensitivity will also be. Ensuring you have a fine grain in shots you take.

So basically, ISO is used to measure the sensitivity of the image sensor in the camera. So what it does is to ensure the sensitivity is low, to get a finer grain in the pictures.

How Does The ISO work?

So this is how the ISO works. The ISO measures the image sensor sensitivity to light. What happens is that the lower the number of the ISO, the lesser the sensitivity of the camera to light. Thereby producing a finer grained picture.

When the number of the ISO is high, then your sensor becomes very sensitive to light.

If you’re planning on manually setting your ISO, then it would be preferable that you increase the numbers in a darker room or space like an indoor sporting event.

How Does The ISO Speed Affect The Photograph?

The higher the ISO speed, the faster the shutter in taking pictures.

When you choose a higher ISO speed, you would have to use a faster shutter speed which is essential in moving subjects like in bird photography. So that if you’re planning on freezing the movement of your shot, it can be possible for you.

For instance, if you use a 100 ISO, you’ll have a clean photo, (with little or no grain or noise), and a crisp shot. But, if the ISO is bumped up, then you might end up having a noisy photo.

When you manually set your ISO, then the shutter speed and the aperture of the camera will adjust to meet that number. Using an ISO setting of 400 will make the shutter speed higher and the aperture smaller.

General Rules When Using ISO

  • There are some rules you need to bear in mind when you’re using an ISO camera setting, some tips on how to use the ISO
  • When the subject is moving, use a higher ISO; this will allow you to be able to freeze the motion and increase the speed of your shutter.
  • If you’re using a tripod, it means you’re trying to stabilize your camera. It will, thus, mean that you’ll lower your ISO number, which will, in turn, slow down the shutter speed. Giving you a more precise photo.
  • For a picture that doesn’t need a high depth of field, you could increase the aperture so that more light can go into the lens. Meaning that the ISO number will be lowered for finer grain. But, you would also consider the difference between the different lens about the aperture value. That they can’t all let in the same level of light.
  • When you’re doing your shoot with artificial light, lowering the ISO will give you a better result.

Some Common ISO values

Here are a few of the ISO values you can find on regular cameras today

  • ISO 100 (some camera can go lower than this like my Nikon D850 base ISO is 64)
  • ISO 200
  • ISO 400
  • ISO 800
  • ISO 1600
  • ISO 3200
  • ISO 6400
  • ISO 12800

The idea is when you double the ISO speed, and you got yourself a high ISO.

What Is Base ISO

Base ISO is the lowest native ISO in your camera. It is a significant setting on your camera. For the very reason that you have the potential to maximize the image quality. And also minimize the amount of noise visibility on the picture.

When you are using an older camera, the base of the ISO is usually 200. But for most of the modern cameras on the market today, their standard base ISO is 100. If you want your picture at its highest quality, then it is best that you leave the ISO at its base.

Now, it’s not like using the base ISO is always possible to get. Because some picture or filming conditions may be in a low-light situation.

How High Can You Set Your ISO?

The highest amount you can set your camera ISO is dependent on the kind of camera you’re using. The ISO of a camera usually starts as low as 200 (or 100 in some cameras), to as high as 64,100.

The number of the ISO usually times itself by two. Until the highest possible number on the camera is reached. When it is twice the ISO, it means twice as much light gathered to the camera.

Low Vs High ISO Noise Visibility (ISO Setting and Grain)

The lower the ISO number, the clearer the picture is.

For instance, if the ISO is 64, then the Grains in the camera will be finer. And you will have a more defined picture than you would get if you set your ISO number to 6400. (Sample Below)

iso photography
@ISO 64


iso camera meaning
@ISO 6400

The difference will be so clear. The one with the higher ISO (that is the 3200 ISO) will be brighter than the lower ISO. And this will also make the shutter speed faster. It is vital that you avoid using the high ISO at all cost. Except in certain circumstances that you are required to use them.

Minimizing Noise and Maximizing Quality

For most of the “experienced photographers” out there, their definition of a quality photo is when the base ISO number setting is to the max.

Although this might be true in some cases, (when you’re shooting a film or taking a photo in a dark area). Using a high ISO speed in a lighted area will only end up maximizing the noise of the photo.

So, using a high ISO doesn’t mean that you’ll end up with noise on your picture. The only time you should use the base ISO is when the lighting in a place is high. Forcing the base ISO in a dark environment will not give you the result you want. Using a high ISO in a lighted environment will only increase the noise in the photo. Thus, high ISO for dark rooms and low ISO for bright environments.


Questions Asked When Choosing ISO

When to use low ISO

Using the lowest or base ISO on your camera should get you the best quality images, but not in all situations. But, the perfect time to use the base or low ISO when there is plenty of light. This will minimize the noise visibility in the camera as much as possible.

There are times when you can still use the base ISO in dark rooms. If for instance, you’re using a tripod stand and the camera is still. Then you can use the base ISO. All you have to do is make the shutter speed longer, this way, you’ll brighten the photo without any noise.

When to use High ISO

The ideal ISO you should use is the low ISO, but there are a couple of times you can use high ISO.

One of the reasons why people end up using the high ISO is because they might have a blurred image when they use the low ISO, and the sharp pictures when using the high ISO.

You just have to keep in mind that high ISO when the place is dark, and that the low ISO works best in lighted places.

How To Change Your Digital SLR Camera ISO setting?

  • Press the ISO button on the camera
  • Next, you’ll use the wheel (left or right) to change the speed on the screen

iso meaning


  • If this option is not on your camera, then you will have to change the ISO setting from your camera menu option

iso camera


You should understand that when the DSLR camera is automatic, then the ISO speed will be set for you automatically. This will suit the lighting level of the environment.


Suggested ISO Setting for Various Shooting Situation

Before I go ahead to give you some suggested settings for your camera, it is pertinent that you know that, the newer the camera is, the better it will be at canceling noise on the picture, than an older camera.

So here are some setting you might want to try out;

1. Capturing the milky way; use ISO 3200

The only time you might get a good photo shooting the milky way is when the aperture lens in the camera is high-speed. if not you’ll need to use the ISO 3200 to gather enough light for your camera to take a clear photo of the milky way.

Night photography means the shutter speed should be no longer than 15 seconds unless you want the stars to have an elongated look.

2. Taking a photo of the sunset; ISO 800

iso definition photography


Although high ISO as this is common to dark areas, there are some pardonable instances when you can use this number on a lighted subject.

Usually, when the sun is about to go down, it is usually at it brightest. But landscape photographers have realized that you’ll get the best photo of the sunset after it has set over the horizon for about twenty minutes. You can use the shutter speed of 2 seconds to get the most effect.

3. Indoor photo with the family, away from the window; ISO 1600

Since you’re in a dark place (even when it’s lighted, it is surprisingly dim). You might want to increase the number so that the lens can get enough light to capture every detail of everyone’s face.

4. Capturing a waterfall; ISO 100

Base ISO is perfect for this scene. But it sometimes would depend on the brightness of the waterfall. Which more often than not is bright and would need a low ISO and long shutter speed.


Common ISO Myths and Misconceptions

For a topic like this, there have to be some myths to it. So I’ll be sharing with you some myths that you should know when using ISO.

1. Is ISO “sensor sensitivity?

The question right here is the most common misconception associated with ISO. It is helpful for you to think that the ISO acts like the sensor sensitivity of the camera. But that is not its function (at the slightest).

The digital sensor on the camera is the only sensitive feature on your camera. The ISO tell you the brightness of the camera needed on a particular scene so that you can give it that level of exposure.

2. Is ISO Part of Exposure

No, no and no, ISO is in no way part of the exposure. The shutter speed and aperture are in charge of exposure by capturing more light into the lens.

What the ISO does it is only to brighten the photo you have taken, according to the number of ISO you used.

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

As intelligent as this question may seem, it is also a misconception that you should avoid. Yes, the act of brightening your photo on a computer is like increasing the ISO, but it is not the case.

The act of raising the ISO on your camera (in particular instances), makes the photo better in quality than increasing the brightness in a computer.



Hope this piece has been instructive and impactful. Because with it, you’re on your way to becoming an expert photographer. It is important to note that raising the ISO on your camera does not always guarantee a good photo. You might end up being disappointed.

Know when to use a high ISO setting so that you can start taking some lovely pictures.

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