To understand one thing it's often helpful to explain it in terms of another. These two devices, a 35mm camera and a human eye, share a lot of qualities.
They both find ways to manupulate light given a set of environmental conditions to render an image. Their shared goals and constraints give rise to similar mechanisms.
There are clearly some significant differences between the two systems, and something may be lost by trying to think of the eye in terms of the camera, but it can also be enlightening.
For me, it's easier to understand the camera, and I can translate that understanding to the eye. In using it, I can manipulate the camera deliberately to see how the different components contibute to the end result.
Using this model––the camera––to describe the target system––the eye––is worthwhile so long as it's useful. If it misses something crucial, then a new model might be warranted.
In this way, computational models help me understand cognition.
