Interestingly people invented cameras before film. Before film came along, people have already been using camera-like systems to make images. A good example is the camera obscura:
The camera obscura is basically a large pinhole camera with a person in it. Instead of capturing the image with a light-sensitive medium like film or a digital sensor, people used to record these images by painting over the projection.
Then light-sensitive materials were introduced. When they were first used in photography, a significant amount of exposure time is required to get a properly exposed image. The picture in the slide was actually exposed over severals days! After decades of development, the film medium became a lot more sensitive and a lot easier to work with. Then digital sensors came along, and we went from recording "chemical" images to digital images.
In computer graphics, we care about creating images from models, or mathematical descriptions of objects in a scene. Like cameras, we care about taking pictures (rendering) but we also care about creating what is outside the camera (modeling). It is interesting to note that regardless of how much technology has changed, not match has changed in the image creation process. As we will soon see in lectures, regardless of how we are actually making an image (hand-painting in a camera obscura, capturing with film or a digital sensor, or rendering with a computer) we are always doing the same thing, sampling.