Detecting the presence of a photogenic subject

Chapter 1, Getting the Most out of Your Camera System, proposed that a photograph ought to capture a subject in a moment. Let's explore this notion further as we search for ways to detect a desirable or "photogenic" subject and moment.

As a medium, photography uses light, an aperture, a photosensitive surface, and time to draw an image of a scene. The earliest photographic technology, in the 1820s, lacked the resolution and speed to convey a detailed subject in a precise moment, but it was able to capture a grainy scene on a sunny day. Later, with better lenses, flashes, and photosensitive surfaces, photography became capable of capturing a sharp scene, a formal portrait, a faster and more natural portrait, and finally a moment of action, frozen in time.

Consider the following series of famous photographs, ranging from 1826 to 1942:

For general interest, here are some details about the preceding photographs:

• Upper left: View from...