how and why lighting affects camera techniques

There are different lighting techniques such as hard lighting, low-key lighting and warm lighting. How you use these types of light can drastically change the mood of your film. 

Hard lighting is mostly used to fake daylight. It is created by one single point light source which means the light rays are pointing towards the subject at the same angle. A hard edge is created on the shadow because all light is travelling from the same angle. Hard lighting is useful in film noir especially when the filmmaker wants to create a silhouette with a sharp edge. 

Soft lighting is created by a broad light source as light is being sent in from all different angles. A soft roll out of light is created when the edge of the object is hit from all different angles at once. A softer shadow is created on the subject or object. When wanting less shadows, soft lighting is used as well as when you want make a subject look better as the lighting is not harsh on the face. 

References:

Marine, J. (2013) Basic lighting lesson: Understanding hard light and soft light. Available at: http://nofilmschool.com/2013/03/basic-lighting-lesson-hard-soft-light (Accessed: 13 September 2016).