First of all, ISO is camera sensitivity to light. Photography is all about light manipulation and letting it work for you. As such, when your camera needs more light, you will need to increase your ISO and when it doesn’t need more light, then you reduce it. This is represented in our chart below
|Less sensitive to Light More sensitive to Light|
|Will capture less light Will capture more light|
|More light needed for ‘good” exposure Less light needed for “good” exposure|
|Less noise More noise|
So, normal camera ISO varies and this means that the lower the number, the less sensitive your camera is to light. The higher the number, the lower sensitive it is to light. As seen in the chart above, cameras with if you have your camera set to ISO 100, it will be less sensitive to light and will capture less light or rather won’t let as much light affect the scene and more light will be needed to have a “good” exposure. It will also have less noise.
If you have to pump your ISO higher, you will get the ability to have more light come in to your sensor, it will capture more light, you will have less light needed for good exposure but you will have more noise. So, when do you need to have an ISO of 100? Normally this is required on a bright situation like when you are taking a landscape photo and it is very sunny outdoors, you will need to keep it 100 and you’ll be fine since the light coming to your sensor is greater. But if you have to increase your ISO, those conditions are normally when you need more light to come in and night time photos is the kind of situation when you need more light to come in to capture good scenes. If you have your ISO set to 100 and it’s dark outside, you will have a very dark scene.
The main drawback of increasing your ISO is noise. Noise grain and image grain will be evident in your images. So, as seen in the video, we have a sporting scene and the image was shot at ISO 100 and there is no noise but it is perfect. As we increase the ISO in the camera, more noise is added to the scene and this can really distract on how a good quality photo can be. That is the main drawback and the reason why many people try to play with the ISO to avoid increasing it more than necessary.
However, sometimes depending on the scene, if you have a lot of noise, that is what you will have in your pictures. In other cases, you might not be able to have that much light coming into your camera due to sensor sensitivity and you will have noise. So, this is basically what ISO is in photography. This is just one part of exposure triangle and you can learn more in our next video.
Visit Sleeklens.com for more topics on Lightroom, Photoshop and other photography-related topics.