What is ISO sensitivity?

How to set the ISO on a camera

What is ISO sensitivity?

ISO sensitivity is used to adapt the camera to different light situations. As we have seen in other tutorials, this depends on three elements:
We will discuss ISO in this article. Increasing the ISO sensitivity of your camera makes it more sensitive to light, which basically means that it will add more brightness to your photo. If the ISO value is higher, then the more light-sensitive the sensor will be. If you want to take a photo in a place that has low light, such as a poorly lit church building, then you will have to increase the ISO, so you don’t get a photo that is too dark (ISO 2,000, for example). It may appear that the best ISO setting is the highest, but remember that ISO sensitivity that is too high produces a negative effect. Generally, we call this effect digital noise. To demonstrate, this “noise” is the small coloured grains that you can see on the right side of the cover photo with the flower. This is the digital noise produced because of the higher ISO sensitivity. So, don’t overdo the sensitivity of your camera.

Adjust the ISO sensitivity of your camera

It is possible to adjust the ISO sensitivity of the sensor of your camera through both automatic and manual modes. Each brand and model of camera offers different sensitivities; for example, the Nikon D700 will allow you to take photos with up to 25,600 ISO. At the same time, a Nikon D5 will be able to take photos with the highest ISO of 3,280,000. 

ISO sensitivity numerically represents the level of this amplification. For instance, ISO 200 is twice as sensitive as ISO 100.

The ISO sensitivity

 ISO 100 – ISO 200 – ISO 400 – ISO 800 – ISO 1600 – ISO 3200 – ISO 6400 – ISO 12800, etc.

Low ISO = less light <=================> High ISO = more light

Between two values on the scale, the sensor in your camera will be twice as sensitive to light, i.e., it will receive twice as much light. In most modes, your camera will automatically choose a suitable ISO setting; therefore, if the light is sufficient, then it will remain at a relatively low value (ISO 100, for example). If it is dark, then your camera will automatically choose a higher value. In addition, you can manually adjust the ISO with the S – M – P – A modes.
To illustrate, let’s take one more picture in the very dark church building. The setting of your camera is in the automatic mode, i.e., “The P mode”, or “A”, or “AV” mode. The camera will measure the ambient light, fully open the aperture, and choose a low shutter speed so that the photo is well exposed. The problem is that the speed will be too slow and you might get a motion blur. To solve this problem, increase the ISO! This will bring a lot of light to the sensor, and the camera will increase the shutter speed. As a result, your photo will be sharp.

Increase the ISO sensitivity for more speed

Let us now imagine a beautiful summer day during which you want to photograph drones in full flight. By increasing the sensitivity, you will force the device to set the faster shutter speed, and as a result, the wings will be sharp.


Advantages and disadvantages of the ISO

The advantages of the ISO

The vital advantage of the ISO is that it allows us to take well-lit photos even in a darker environment. By increasing the brightness, we can increase the shutter speed, or close the aperture in order to get a greater depth of field.

The disadvantages of the ISO

If you keep the ISO too high, then it will end up adding digital noise in your photos. Software, such as lightroom, can be used to reduce the digital noise in a photo.

Photo edited in Lightroom.


The lower the ISO, the less sensitive your digital sensor will be to light and the dimmer your photo will be. The higher the ISO, the more sensitive your digital sensor will be to light and the brighter your photo will be (but be careful about noise). So, now you know what ISO sensitivity is. Please give us your opinion, and also share your experience in the comments.
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Have a nice photoshoot!

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