Unraveling the Mystery of ISO – Tips for Setting ISO in Different Situations

In the world of photography, the “exposure triangle” of aperture, shutter, and ISO is the main element that constitutes a photo. As long as you understand the combination of these three things, you can basically take photos with no blur and correct exposure. But many newbies don’t know when to use the value of ISO. This article is to solve the mystery of ISO! Take a look and learn together!


What is ISO?
ISO can be called “light sensitivity”. In the old film, the ISO value is fixed, that is, if you use a film of ISO400, you must complete the whole cylinder of film before you can replace it, but in the digital age, ISO can be changed at will to match the ambient light when shooting, which is very convenient, so we should make good use of the benefits of this technology to help us take beautiful photos!

As soon as you enter the room, even if the human eye feels that the brightness is sufficient, there is a high chance that you must use ISO800, ISO1600, etc. to shoot handheld.

Shooting moving objects (such as racing cars, children, pets, etc.), even outdoors, a higher ISO can increase the shutter speed and help take clear photos.

Low ISO helps to reduce light absorption. With ND filter, you can use slow shutter speed to shoot flowing water in broad daylight.

The signal noise will be obvious only in the dark position of the photo, but not very visible in the light position. Therefore, the signal noise will be less affected when using high ISO in the daytime.

Auto ISO setting
If your camera has the “Auto ISO” function, you can turn it on when you are shooting by hand, so that the camera will automatically increase the ISO to a suitable position according to the current light, aperture and shutter speed. Some cameras will automatically detect the used camera. The focal length is used to set the ISO, so that the shutter can meet the requirements of “safe shutter”, which is very convenient!

“Auto ISO” usually has two settings, one is “highest ISO” and the other is “lowest shutter”. The former is used to limit how much the camera can raise the ISO. Usually, I will set it to the next highest ISO available to the camera. For example, if the maximum ISO is 6400, it will be set to 3200 (the second highest). The automatic boost should be set according to the actual needs and the focal length used, so as to meet the “safety shutter”.

What if the lens/body has anti-shake function?
If the lens/body has an anti-shock function, you can set the ISO to a lower value when holding the camera, so that the shutter can be slow, and the photos taken with the anti-shake function will be clear and reduce noise.