How to select the best ISO setting
The ISO in the camera control how sensitive is the sensor to the light. You can make a search to learn more about how the sensor works. This article is more about how to used it to take better pictures.
In most camera the ISO start at 100, the lowest the number the less sensitive is to the light and the opposite, the bigger the number the more sensitive is to the light. But using big ISO make you camera to produce noise in the picture.
In film photography you have grain and its quite an style, but in digital photography noise it seen with bad eyes.
The trick to select the best ISO possible for your photography its knowing the three aspect of exposure. Aperture, shutter speed and ISO. Example if you are in a low light room and the depth of field its not a problem, you have your aperture set to the biggest you have, and your shutter speed is as slow as possible without causing motion blur, and the photos are under expose then you can rise the ISO until you have a good exposure.
Remember a good exposure reduce the noise in high ISO and beside if the people notice the noise in your photos maybe you don’t have a strong picture. Be creative an use the noise to your advantage, start shooting and making good picture
Now go out and shoot!