Home Articles & Reviews What exactly is ISO? The Complete Beginner’s Guide

What exactly is ISO? The Complete Beginner’s Guide



  • What is ISO?

  • What Does ISO Stand For?

  • Common ISO Values

  • What is Base ISO?

  • How to Modify ISO:

  • What ISO Should You Use on Your Camera?

  • Noise reduction and image quality enhancement

ISO is one of the three pillars of photography (the other two are shutter speed and aperture), and it has a significant impact on the quality of your photographs. What effect does the ISO setting on your camera have on your photos? In this tutorial, we’ll cover the basics of ISO and show you how to utilise it properly to get the greatest results.

What is ISO?

ISO is a camera setting that brightens or darkens a shot in the most basic sense. Your images will get more brighter as you increase the ISO setting. As a result, ISO can assist you in capturing photographs in low-light situations or allowing you to be more flexible with your aperture and shutter speed choices.

However, increasing your ISO has drawbacks. A photograph taken with a high ISO will have a lot of grain, also known as noise, and may be unusable. As a result, increasing the ISO to brighten a shot is always a trade-off. Only increase the ISO if you are unable to brighten the image using the shutter speed or aperture.

What Does ISO Stand For?

The ISO (International Organization for Standardization) acronym stands for “International Organization for Standardization.” Camera ISO, on the other hand, does not relate to the organisation that develops numerous technical and product standards. Since 1974, when two film standards, ASA and DIN, were unified into ISO standards (later amended for both film and digital photography), they have been referred to as “ISO.” Although ISO was originally designed to describe solely film sensitivity, it was eventually adopted by digital camera makers in order to retain film-like brightness levels.

Common ISO Values:

You can use a different range of ISO values (al so known as ISO speeds) depending on the camera. The following is an example of a common set:

  1. ISO 100 (low ISO)
  2. ISO 200
  3. ISO 400
  4. ISO 800
  5. ISO 1600
  6. ISO 3200
  7. ISO 6400 (high ISO)

Simply said, double your ISO speed doubles the brightness of your photograph. As a result, a photo taken at ISO 400 will be twice as bright as one taken at ISO 200, which will be twice as bright as one taken at ISO 100.

What is Base ISO?

Your “base ISO” is the lowest native ISO on your camera. This is a crucial setting since it allows you to achieve the best image quality while reducing the visibility of noise as much as possible. Most modern digital cameras have a base ISO of 100, however some older DSLRs and a few recent cameras, such as the Fuji X-T2, have a base ISO of 200. To acquire the best image quality, you should always attempt to keep to the basic ISO. However, this is not always practicable, particularly when working in low-light situations.

Noise Visibility at Low and High ISO:

Take a look at the comparison below for an example of two images taken at different ISO levels. Pay attention to the amount of noise in the photographs (graininess and blotchy colours):

The difference is obvious: the ISO 3200 image has significantly more noise than the ISO 200 shot (which I brightened with a long shutter speed instead). This is why, unless circumstances dictate it, you should avoid using high ISOs wherever possible.

How to Modify ISO:

Changing the ISO on a camera differs from one to the next. Here are a few common methods for changing ISO:

  • To begin, select a mode that allows you to choose your own ISO. Change to Manual, Shutter Priority, Aperture Priority, or Program from Auto (we tend to prefer Aperture Priority or Manual).
  • You’ll probably need to open a menu (perhaps the “fast menu”) and find the ISO section for entry-level DSLRs and mirrorless cameras. Set the value to whatever you wish, or leave it at Auto.
  • There may be a dedicated “ISO” button on the camera for higher-end cameras. To adjust your ISO setting, press it while spinning one of the wheels. Even if your camera doesn’t have an ISO button, it’s feasible that you can programme one to accomplish this function.
  • Other cameras may have a specialised ISO wheel with several ISO settings already marked. This simplifies things even more.

If you’re still unsure, see your camera’s handbook. However, knowing how to quickly alter your ISO level is important, as you’ll likely be doing it frequently, especially if you’re shooting in low-light situations without a tripod or flash.

What ISO Should You Use on Your Camera?

Many photographers are familiar with the fundamentals of ISO, but are unsure which ISO setting to use in the field. In practise, there’s a reason your camera has so many ISO options: different scenarios necessitate different ISOs. We’ll go over some of the most common circumstances you’ll encounter below.

You might be able to use a low ISO even in dim or gloomy conditions. If your camera is mounted on a tripod or is totally steady on a table, for example. Because you won’t add camera shake, you can safely utilise a low ISO and brighten your photo with a lengthy shutter speed instead.

When Should You Use a High ISO?

Even while using low ISOs is preferable, there will be occasions when a high ISO is required to shoot a good photo in the first place. The basic reason for this is that you will frequently be fighting motion blur, and you will have to choose between a sharp photo at a high ISO and a fuzzy photo at a low ISO. Take a look at the following image:


These Black Skimmers were photographed at 1/2000th of a second at ISO 800. My camera needed 1/2000th of a second to completely freeze the birds in mid-flight. What would have occurred if I had instead set my camera’s ISO to 100? To get a bright photo, I would have needed a shutter speed of 1/250th of a second. Because the birds were moving so quickly, there would have been a lot of undesired motion blur in the photo at that level. To put it another way, I would have damaged the image.

The main line is that if there isn’t enough light for the camera to obtain a sharp, brilliant snapshot any other way, you should increase the ISO. I always adjust my ISO to a higher number while shooting handheld photographs indoors without a flash to catch the moment without introducing fuzz. When photographing ultra-fast action, such as the bird snap above, you may need to increase your ISO.

Auto ISO is a feature found on most cameras that performs well in low-light situations. The beauty of this setting is that you may specify the highest ISO you’re willing to utilise, and the camera will not exceed that value. If I want to keep the amount of noise in a photo to a minimum, I’ll use ISO 800, 1600, or 3200 as my maximum ISO. If the camera hits these ISO limitations, it will start using progressively longer shutter speeds, resulting in increased motion blur. Everything is a compromise!

Noise reduction and image quality enhancement:

Some photographers believe that using Base ISO 100 percent of the time is the best method to obtain high-quality photographs. However, as seen above, this is simply not the case. You may find yourself in situations when you have no choice but to use a higher ISO.

When there is adequate light, you should merely utilise base ISO. In a dark atmosphere, don’t try to force ISO 100, as your images will be far too dark. Similarly, capturing activity with a quick shutter speed is practically the same as taking images in a dark setting (since you strictly limit the amount of time your camera sensor is able to capture light). As a result, a high ISO may be your only option for certain sorts of sports and action photography.

Here are the four actions you must take to improve the quality of your image:

  1. Choose the aperture that will give you the depth of field you want.
  2. Set your ISO to its default value and your shutter speed to whatever level gives you the best results.
  3. If your subject is fuzzy, gradually increase the ISO while using a quicker shutter speed until the motion blur is gone.
  4. If your ISO is getting too high and you can still use a wider aperture, do so until the ISO drops to a more manageable level, even if it means losing some of your ideal depth of field.

That’s all there is to it! If you follow these instructions, you’ll always get the best image quality. The perfect balance of noise, motion blur, and depth of field will be found.

Myths & Misconceptions About ISO
There are a lot of misconceptions about ISO, including some that are extremely popular. We’ll quickly answer some of those issues in this section so that you’re not mislead about this topic in the future.

I hope you like this post, if you have any queries you can ask me on the comment section. And don’t forget to like this post and share it your photography lovers friends and family.




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