Soft light is when there is a lot of light and a smaller subject. Hard light is when the subject is bigger than the amount of light. You use hard lighting to create a high contrast look and it will create shadow. You use soft lighting to create a flatter contrast look and the highlight it creates holds more details. In order to use hard and soft lighting you have to decide what lighting setup will create the look you are going for. To use hard light you must have a single light source aimed from a distance onto an object. To use soft light set up a larger light source closer to your object. The subject will have a major influence on your choice of light source. Using portrait is important in creating a bigger light source for hard and soft lighting.