Source from the internet
what is ISO ?
In Digital Photography ISO measures the sensitivity of the image sensor.The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain.Higher numbers mean your sensor becomes more sensitive to light which allows you to use your camera in darker situations. The cost of doing so is more grain (although cameras are improving all the time and today many are able to use high ISO settings and still get very usable images).
An example of a situation you might want to choose a higher ISO would be photographing an indoor sporting event where the light is low and your subject is moving fast. By choosing a higher ISO you can use a faster shutter speed to freeze the movement.
In Digital Photography ISO measures the sensitivity of the image sensor.The same principles apply as in film photography – the lower the number the less sensitive your camera is to light and the finer the grain.Higher numbers mean your sensor becomes more sensitive to light which allows you to use your camera in darker situations. The cost of doing so is more grain (although cameras are improving all the time and today many are able to use high ISO settings and still get very usable images).
An example of a situation you might want to choose a higher ISO would be photographing an indoor sporting event where the light is low and your subject is moving fast. By choosing a higher ISO you can use a faster shutter speed to freeze the movement.
Source from the internet
Is it better to have a low or high ISO ?
As you go increase your ISO, you start to introduce “digital noise” to your image. Similar to film, which has more and more grain the higher you go in ISO film speed, digital sensor creates more and more noise as you increase your ISO. Noise is the by-product of the increased electric charge needed to make the sensor more sensitive to light and looks like speckles on the image. The consequence of more noise, however, is a rougher-looking image and a decrease in image quality. There are two types of noise, luminance noise, and chroma noise. Luminance noise retains much of the original color because this type of noise only affects the brightness of the pixels. Chroma noise, on the other hand, looks like colored speckles or grain, and is largely unattractive. This is because the noise is affecting the color of the pixels rather than just the brightness of the pixels. Luckily, post-processing software like Lightroom 4 does a good job in minimizing chroma noise.
As you go increase your ISO, you start to introduce “digital noise” to your image. Similar to film, which has more and more grain the higher you go in ISO film speed, digital sensor creates more and more noise as you increase your ISO. Noise is the by-product of the increased electric charge needed to make the sensor more sensitive to light and looks like speckles on the image. The consequence of more noise, however, is a rougher-looking image and a decrease in image quality. There are two types of noise, luminance noise, and chroma noise. Luminance noise retains much of the original color because this type of noise only affects the brightness of the pixels. Chroma noise, on the other hand, looks like colored speckles or grain, and is largely unattractive. This is because the noise is affecting the color of the pixels rather than just the brightness of the pixels. Luckily, post-processing software like Lightroom 4 does a good job in minimizing chroma noise.
In this series I wanted to show how ISO and the higher the setting you put it on the brighter it gets. It goes from auto to 100 all the way to 6400 it has it has 7 setting options on ISO then it has an auto button.
In this series I went from Auto to 6400 on ISO to show how it gradually get brighter.
Best and Worst
The on the left is better because it is not too bright or dark but the one on the on the right is too bright you can hardly see the cones.