2424 PART 2 HOW DIGITAL CAMERAS CAPTURE IMAGES
A CENTURYand a half ago, when photography took its first steps into journalism, family portraits, landscapes,
and wars, the process of capturing images was relatively simple because the cameras of that time were far less versa-
tile than the cheapest disposable camera of today. There simply wasn’t a lot that a photographer could do with a
camera other than make sure the picture was in focus, that the exposure was correct, and that the camera was
pointed in the right direction.
At the same time, that meant whatever the photographer did was entirely a measure of the photographer’s skill with
his equipment. The photographer couldn’t amaze his customers with brilliant colors; most photos were black and
white with perhaps same pastel shading added by hand. People didn’t look for a photographer to capture the inner
soul of Uncle Vernon; they simply wanted Uncle Vernon to be recognizable, which was as awe-inspiring then as live
videos from space are today. There was no opportunity for shooting test Polaroids, for studying histograms showing
the range of exposure, nor, in many cases, even a second chance. The process was tedious and tiring not only for
the photographer, but for the subjects, who were often asked to remain motionless for unnatural spells, all the time
encased in their best, but stiff and hot, Sunday go-to-meetin’ clothes. With no more than two or three chances to get it
right, the photographer had to know exactly what his camera could and couldn’t do.
Focusing was the simplest task. At the back of the camera, spring-loaded brackets held a frame containing a sheet of
film shielded from the light by a metal slide. The photographer covered the back of the camera with a black cloth,
stuck his head under the cloth, and removed the film holder. In its place was a sheet of glass roughened on one side.
The roughness caught the light so that it didn’t simply pass through the glass but instead formed an image—upside-
down to be sure—coming through the lens. The image from the lens rode the light waves to the focusing glass
through a billows made of leather. A track and gears beneath the billows let the photographer move the lens back
and forth until the image was sharp.
Exposure was trickier. There was no diaphragm to control how much light was allowed to expose the film nor shutters
to control how long the film was exposed. In place of both, there was a lens cap. The photographer simply removed
the lens cap so light could stream through the lens. Luckily film of that time was so insensitive to light that exposures
less than a second or two weren’t even a consideration.
No matter how advanced your camera you still need to be responsible for
getting it to the right place at the right time and pointing it in the right
direction to get the photo you want.
Ken Rockwell,
Your Camera Does Not Matter