Difference Between ISO and Shutter Speed

Key Difference – ISO vs Shutter Speed

The camera ISO, shutter speed, and aperture are considered as the pillar of photography. The key difference between ISO and shutter speed is that the ISO is connected to sensitivity whereas the shutter speed is connected to the amount of light that touch the sensor. Both the values ultimately affect the exposure and quality of the photo. A photographer has to master the use of the above 3 elements to become proficient in their pursuit of capturing great photos.

What is ISO?

The ISO can be referred to as one of the three pillars of photography. The sensitivity to available light can be defined by the ISO. The lower the ISO, the less sensitive the camera is to light, and the higher ISO gives higher sensitivity to light. The camera sensitivity is controlled by a component called the image sensor. This is the most expensive part of the camera and is responsible for converting light into an image. The increase in sensitivity can be used to capture images in low light without the flash, but the tradeoff is that, when increasing the sensitivity, it will result in grains or noise added to the image. This in turn will result in a drop in quality of the image.

The base ISO is the minimum ISO that can be used to create an image without adding any noise. This will provide us with the highest image quality for the lowest ISO number. But in low light conditions using the base ISO is not always possible. The ISO number geometrically progress in the following pattern: 100, 200, 400, 800 and 1600. When moving on from one ISO number to the next ISO the sensitivity typically doubles.

When the ISO value is low, more light is needed for exposure. For this purpose, slow shutter speeds should be used. On the other hand, if a higher ISO value is used, faster shutter speed should be used which is ideal for sporting and indoor photography.

When the need is for a detailed shot, the lowest ISO number should be used. When there is great lighting, the low ISO number will produce you with the highest image quality. This will also have the highest detail in an image. When there is not enough light, to increase the sensitivity of the camera, the ISO should be increased. When the ISO is increased, the camera is capable of capturing images involving movement. The higher ISO number will be ideal for indoor photography to capture and freeze motion with a fast shutter speed. The auto ISO feature sets the ISO rating to a specific number according to the surrounding light that is available. This will make sure that the camera setting does not surpass the maximum ISO amount and add too much noise to the image.

Key points to note when selecting ISO

• When we need to capture motion, to reduce the blur, a higher shutter speed is needed. To compensate for the higher shutter speed, a higher ISO should be considered.

• For black and white photography, increasing the ISO and adding noise will not be a problem.

• With the use of a tripod, slow shutter speeds can be accommodated, so that, lower ISO can be used.

• When increasing the aperture of a camera, it allows more light into the sensor. So a lower ISO can be used. This setting is usually used when the need is not the depth of field.

• In artificial light, lower ISO is preferred.

Difference Between ISO and Shutter Speed

What is Shutter Speed?

Shutter speed is also one of the pillars of photography along with ISO and aperture. The shutter is located in front of the camera sensor. It remains closed until the photographer takes a picture. When the camera fires, the shutter opens and lets in light onto the sensor through the aperture of the lens. After the sensor is exposed to enough light, the shutter closes. This will stop the sensor from getting exposed to further light.

The shutter speed is the time that the camera sensor is exposed to light with the use of the camera shutter. By using a fast shutter speed, we are able to freeze the motion whereas, with a lower shutter speed, we can create motion blur. Slow shutter speeds are also used in lightning photography and also in capturing images like landscape photography.

Shutter speeds are measured in fractions of seconds. Some DSLRs are capable of supporting shutter speeds up to 1/8000th of a second. The longest speeds that can be achieved by the shutter is 30 seconds. When using slower shutter speeds, image stabilization feature is very useful as it will compensate if there is any shake during the photography. Otherwise, a tripod should defiantly be used to avoid blur in an image.

When using faster shutter speed, the picture is usually darker, contains less blur and the fraction of seconds is small. When using a slower shutter speed, the picture shot is brighter, it contains more blur, and the fraction is larger.

Key points to note when selecting Shutter Speed

• When using a lower shutter speed, a tripod or image stabilization feature is needed.

• The shutter speed is of concern when shooting moving objects. If moving objects are available, faster shutter speeds should be used to avoid blur.

ISO vs Shutter Speed - Key Difference

What is the difference between ISO and Shutter Speed?


ISO: ISO is involved with light sensitivity.

Shutter Speed: Shutter speed is involved with the amount of light.

Unit of Measure

ISO: ISO is measured in numbers.

Shutter Speed: The shutter speed is measured in a fraction of seconds.


ISO: ISO is all about light sensitivity.

Shutter Speed: Shutter speed values have the ability to freeze a moment in time.

Selection of ISO and Shutter Speed

ISO: The lower values of ISO are usually the best for photography. Higher ISO values unusually add grain or noise to the image.

Shutter Speed: Slower shutter speeds can be used in various situations to create breathtaking imagery. Eg: waterfalls, a moving racing car, shots involving movement for a long period of time. It is possible to make use of low and high shutter speeds in order to create beautiful images, according to the need.

Working Mechanism

ISO: ISO is virtual

Shutter Speed: The shutter speed works mechanically.

Effect on Pricing

ISO: The ISO is related to the sensor, which is the most expensive part of the camera.

Shutter Speed: The shutter is less expensive comparatively.


ISO vs. Shutter Speed

If we take a closer look at both, mastering both the features are very important in photography. According to the photographic situation that arises, the need to adjust these settings in a smart way is very important in the output of the photo.

The higher shutter speed is used for freezing motion whereas the lower shutter speed is used to create motion blur. On the other hand, the lower ISO setting is used in bright situations to capture clear, detailed images. The Higher ISO value is used in sport, indoor photography where lighting will not be that great.

Image Courtesy:
Image 1: "E17 - korte sluitertijd" [Public Domain] via Wikimedia Commons and "E17 - lange sluitertijd" [Public Domain] via Wikimedia Commons
Image 2:  "Flower at 100 ISO for comparison" by Andrew Hutton HuttyMcphoo - Own work. [CC BY-SA 3.0] via Wikimedia Commons and "Flower at 1600 ISO for comparison" by HuttyMcphoo - Own work. [CC BY-SA 3.0] via Wikimedia Commons