Designed for use in studio photography but also used for off-camera flash and portable lighting kits, light modifiers allow photographers to control and change the power, direction, size, shape, and even colour of the lighting source.
Lighting modifiers include collapsible refelctors that collapse down into a portable and easy to carry form; these reflectors can be used in either daylight or with flash lighting to reflect light into the shadows.
Other lighting modifiers include umbrellas - these are usually mounted onto a flash head or flashgun and can either be reflective or shoot-through. Umbrellas are used to soften the light, similar to how a softbox works. However, softboxes direct the light into a wide angle, whereas umbrellas usually allow more light-spill.