The most important thing in photography is the light. Cameras settings, are all different ways to alter light. In shooting light equipment is necessary in order to take a good picture at times. In photography there are generally two lights one can use, a flash head and a power pack or a monolight which is a light stand with its power built in. Flash packs are basically multiple “heads” (the parts that emit light) and its separate power generator (the power pack) that emits voltage, when transmitted into the heads they create a flash of light.  The symmetric power packs emit voltage equally into every head (equal lighting) and the asymmetric lights allow for one to manually be programed to emit greater light. Mono lights on the other hand are more like a regular flashlight which makes them convenient for moving around. Other devices you could use to modify the lighting on pictures are the light modifiers. These modifiers are things like reflective umbrellas which help create a softer light tone for images by basically spreading the light in a lighter tone and spreading it out more. Some other devices would consist of soft boxes which are similar to reflective umbrellas except their light is far more focused and tone is not as light.