The casing protects and holds all the parts inside the camera, also it prevents light from coming in contact with the film
The shutter controls how long the film is exposed to light when taking a picture.
The lens redirects the beams of light to form a photo
The film helps capture the photo. The light reflects off a subject and hits the lens, it then strikes the emission to record the image
The flash circuit increases the amount of light in a given area.
The gas discharge tube conducts electrons to produce a flash of visible light.