Armed with a digital camera and his computer, he produced a portfolio of amazing pictures, using a bewildering arsenal of image-processing techniques. His view of photography could not be more different from mine. The questions that I find so intractable are not even an issue for him. For Graham, a photograph is something to digitize and to start to play with. And so, like many a parent of teenagers, I find myself looking at the world through new eyes.

Our family debate echoes a larger controversy that is now raging in the field of nature photography. A recent book, Virtual Wilderness: the Nature Photographers Guide to Computer Imaging, by Tim Fitzharris, extols the creative potential of digital techniques for manipulating scanned photographs. It includes some incredible images, of such things as elephants (photographed in Africa) climbing glistening white sand dunes (photographed in New Mexico), and of wolves (photographed in an enclosure) placed against a wilderness background (from Alaska), with their howling muzzles dramatically emitting cold clouds of mist (digitally fabricated). There is a growing movement that asserts that such manipulation, when unacknowledged, amounts to falsification, and undermines the veracity of nature photography as a documentary medium. A grassroots program called “FoundView” has sprung up, to support photographers who certify that no elements of an image have been altered (except tonally) since the shutter was clicked. This is so-called “single-click photography”, which is growing in acceptance as a standard for reality-based imaging.

Now, I don’t consider myself a purist by any means. I accept that photography, by its very nature, is a highly artificial and selective act. Like virtually all photographers, I use filters and manipulate depth of field to create images that my eyes could never see, and my son has shown me that brilliantly creative and evocative images can result from digital manipulation. What I find troubling is not the technology but the ideology. To my mind, a photographer - like an ecologist and a land manager - is a student of nature, not its master. Digital manipulation of images troubles me to the extent that it divorces us from the natural moment, that it fosters an illusion of control. “Virtual wilderness” is not merely a contradiction in terms; it is a dangerous delusion.

I guess what I hope for from my son is simply the acknowledgment that there is such a thing as the irreplaceable moment. There is a sacredness in that instant when a breeze stirs a meadowful of camas flowers; when the scream of a hawk suddenly fills a silent canyon; and when the deer turns its head and looks straight into your eyes. The only way to have these moments is to be there. For most of us, days and weeks and months of our lives may pass without leaving a trace of lasting memory. But those moments of “being there”, measured out in seconds, will remain with us to the end of our lives, worn smooth and familiar by recollection.

Constantly surrounded as we are by devices that produce and reproduce images and sounds, we are in danger of losing the unmanipulated moment. What will that mean? It is hard to know -- such a situation is new in the history of life. But I fear that the glare of the image will come to blind us to the shape of the absolute. Paradoxically, drunk with images, we will be left at last without vision. At that moment, we will find that we are lost indeed.