ISO is the amount of light being allowed into the sensor of any given camera. For half of these pictures I changed the ISO and stood in front of the classroom- 100 being the lowest, making it dark, and 3200 being the highest, making it bright. For the other half I went outside and did the same thing, some of them dark and some of them bright because of the ISO that it was set at for the picture. As the ISO got higher it allowed more light into the camera, and as it got lower it blocked out light not needed. The first half of the pictures are almost not visible, because there was little to no lighting in the room so setting it at a low ISO means there would be no light. The highest ISO is almost too bright, because it allows a lot light into the picture.