A digital camera is essentially a computer with a lens attached to it. Its functions are fully automated, so you can take decent pictures without having to do much more than point the camera and shoot. Everything changes, however, when you shoot in the dark. To get decent pictures, you have to switch to manual mode and make careful adjustments to ISO settings, shutter speed, aperture and focus. A lot of this is trial and error. ISO settings should be as low as possible so you don’t wind up with a lot of image noise – the digital equivalent of graininess in film images taken in low light. Automatic focus doesn’t work well in the dark, and manual adjustments aren’t much better because you can’t see clearly. And since exposure times are now calibrated in seconds rather than fractions of a second, you are better off using a tripod and shutter release cable; otherwise, your images are likely to be spoiled by camera shake. At least with digital cameras, you are not using up a lot of film trying to get the picture to come out right – and you don’t have to wait for your film to be developed to find out.
The limitations of cameras shooting in the dark point up just how well engineered the human eye is by comparison. As you may remember from biology class, our eyes have two kinds of photoreceptor cells: cones, which work best in bright light; and rods, which are much more numerous and can be triggered by a single photon, making them most effective in low light. Together they enable the human eye to maintain sensitivity to brightness over nine orders of magnitude (about one billion times). The eye adjusts automatically to changes in illumination, although it may take the rods a half hour or longer to adapt fully to darkened conditions after exposure to bright light.
Seeing in the dark also has its spiritual uses. Normally we invoke imagery of light to characterize spiritual experience. Think of St. Paul on the road to Damascus, when he had his encounter with the risen Christ. He was dazzled by the light. The contrast could not have been greater on the day the Lord God Almighty first made his covenant with Abram (later renamed Abraham). According to the King James translation of the Genesis account, Abram fell asleep and “an horror of great darkness fell upon him.” The as-yet childless patriarch had been promised that his descendents would be as numerous as the stars in heaven. But now he learned that they must first go down into Egypt, where they would be enslaved for 400 years. Light and darkness in these two encounters are essentially reversed from the way we normally think of them: St. Paul is blinded by the light, whereas Abram is shown things in the darkness that are normally veiled from mortal sight.
Spiritual darkness need not be the horror that descended upon Abram when the Lord made his covenant with him. There is also that “deep but dazzling darkness” that the 17th-century metaphysical poet Henry Vaughan speaks of in “The Night” above. The prophet Isaiah is getting at something similar when he quotes the Lord telling him, “I will give you the treasures of darkness and the hoards in secret places, that you may know that it is I, the LORD, the God of Israel, who call you by your name.” The Psalmist likewise testifies that God “made darkness his secret place; his pavilion round about him were dark waters and thick clouds of the skies.”
The darkness referred to in these passages is not literal. As the anonymous author of The Cloud of Unknowing describes it, this darkness is not an absence of light but rather something that cannot be grasped directly by the senses or by the intellect. His classic work on contemplative prayer states that when you first approach God
all that you find is a darkness, a sort of cloud of unknowing; you cannot tell what it is, except that you experience in your will a simple reaching out to God. This darkness and cloud is always between you and your God, no matter what you do, and it prevents you from seeing him clearly by the light of understanding in your reason, and from experiencing him in sweetness of love in your affection.
As one becomes accustomed to seeing in the “divine dark,” as Dionysius the Areopagite once called it, another strange sort of reversal takes place. Things that appear solid by the light of day now become invisible, most notably the self by which all else has been apprehended. The intellect having at last abdicated its throne, we find ourselves joyously dissolved into the dazzling darkness.