ISO is used to determine how much light is let into your camera, and is useful when trying to make your images look neat. A high ISO is typically used for low lighting, as it can make your image look more clean, but can also make your image look noisy if you aren’t on the correct ISO needed for the image. Whereas, a low ISO is usually used for a light lit image, so it doesn’t look noisy. An image can end up looking noisy if you are using a high ISO when it’s not needed (like if your image doesn’t have low lighting).

In the image above, you can see that the high ISO makes the image look grainy and noisy, which isn’t ideal when you want a clean look for your image. To prevent this, you need to ensure the lighting is good and that you are using the right ISO.

My Contact Sheet

These are the images I took to show the contrast in lighting and the ISO difference by increasing and decreasing the ISO number.

I put the two images above to present a change in ISO and the lighting, so you can see each stage of the process.

I also decided to include this image above as I feel as though it represents the noisy ISO that we are usually trying to avoid in our images. As you can see, the lighting isn’t the best in this image, and the ISO number is on the lower side making the image not look the best it can.