edge-case Noun. (plural: edge cases)
A problem or situation that occurs only at an extreme (maximum or minimum) operating parameter.
Film photographers had a clear understanding of how film behaved when over-exposed or under-exposed. The edge-cases for film were simple, predictable, and the same in any camera.
Digital cameras are a different story. Each has an image-processing chip programmed to produce the “best” possible image, each in its own way. Worse, there’s no means to find out exactly what it’s doing.
For a selfie in sunlight, all digital cameras do what’s expected. It’s the edge-cases where we see the processor still struggling to produce a “best” image, and in that struggle, producing the unexpected.
When enlarged, or contrast enhanced, complex, even painterly rendering is revealed, constructed by the machine in ways likely not anticipated even by the system’s programmers.
In this way, the digital camera at its edges becomes, in its own right, a new medium.