Light entered the front of the camera (yellow) through the aperture and lens (red) and hit a piece of film (green) wound out from the spools at the back (brown). Note the sprocket holes at the top and bottom for winding the film accurately through the camera.īefore digital cameras came along, photography involved capturing light rays on silver-based film, as shown in the picture below. So a roll of film with 36 frames on it would be about nine times this length. You can just about make out that there are four "frames" (individual pictures) here, side by side. Photo: A typical piece of 35mm color photographic film. Ultraviolet X-rays, or whatever you wish.) (Incidentally, light doesn't just mean visible light: you can, in theory, make a photograph from any kind of The light energy leaves a permanent traceīy causing a chemical and physical transformation of the film. In a traditional camera, there's no chip instead, the incoming energy isĬaptured by a piece of plastic that is sensitive to light, better Immediately behind the lens, which converts the light energy into electricity. (either a CCD (charge-coupled device) or an alternative That happens because there's an electronic light-detector chip
Remember that light is a form of energy what a cameraĪctually does is permanently capture the energy falling on a small, (two-dimensional) surface So what does happen? It always helps to think like a scientist! They don't move back andįorth, thoughtfully scribbling out a picture like an artist's hand. "Photography" is a bit of a misnomer: it's not really true to say that light rays But the crucialĭifference between a camera and your eye is that a camera makes a Light charging in through a lens at the front. Much like the human eye, a camera captures rays of Moon) in rays that zoom into our eyes in perfectly straight lines. Light (like the Sun) or reflect it off their surface (like the (writing)-so photography effectively means "writing with light."īut that's just a metaphor.
Let's take a closer look at how they worked! They can actually teach us quite a bit about chemistry, physics,Īnd the science of light.
Still use film cameras, most of us have long since abandoned them to history,Īlong with steam engines and the telegraph. Wasn't possible because cameras worked differently: they wereĮntirely analog, capturing pictures as patterns of light andĭark using chemically treated reels of plastic film, andĪ photograph took hours (or even days) to appear in your hand. Ways: you can instantly email it to a friend, upload it to a website, Of digital information you can use in all kinds of different Snap a photo with your camera, cellphone, or
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