Estes Park, Colo.: Early on an autumn morning, a light confection of snow begins dusting treetops on the eastern edge of Rocky Mountain National Park. We’ve pulled our 4×4 to the side of the road, and I’m huddled low by the fender to line up my camera for a shot of four approaching elk. My guide, wildlife photographer Steven Morello, whispers to me from the driver’s side. No abrupt moves, he cautions; if I stay quiet, I’ll probably get a long shot of these animals when they amble up the hill to our right.

Three of them do exactly that. But the fourth, a young stag with an impressive set of antlers—impressive to me, anyway—makes an unexpected turn and saunters straight in my direction. He stops briefly, swings his head to scan me with his opposite eye, and practically poses for a quick portrait. I hadn’t expected this to be quite so easy.

Slide Show: Images from Safari

I’ve come to Colorado to experience an increasingly popular form of ecotravel, loosely known as a “photo safari”: a guided trek to some pristine outback of the globe, with the goal of capturing one of those screensaver images that make us gush over the grand visual spectacle of planet Earth.

The ruling mantra of the photo safari is “patience.” You wait for that moment when light reflects, just so, off a lake; you wait for the giraffe to scan the horizon for predators before it dips its head to drink. In my current situation, however, I didn’t have to wait long. Morello had promised over breakfast that we’d photograph some elk today. “You’re good,” I tell him. “We haven’t been on the road 20 minutes, and I’ve already got a shot.”

The stag, however, has another surprise for us. Rather than shying when he hears the shutter release, he resumes his steady plod directly toward me. Morello’s tone abruptly changes. “Don’t move,” he instructs, as the animal edges close enough to sniff at my woolen scarf. Over my head, his antler points scratch against the Jeep. Even though this odd behavior creates the illusion of a convivial moment, I’m acutely aware that it’s probably not. Frozen between fender and elk, I stage-whisper in Steve’s direction: “What am I looking at here?” He seems as puzzled as I am.

To be fair, I couldn’t call this moment especially terrifying. It wasn’t exactly a rhino attack, but the animal wasn’t Bambi either. If I were to make a sudden move his antlers could clearly do some damage when he bolted. Morello gently taps the car roof a couple of times; the elk backs up a little, then bounds off to rejoin his companions.

Morello later speculates that this quirky elk was habituated to humans, probably as a result of hand-feeding, one of the more egregious violations of the photo safari’s maxim for behavior in the wild: “Take only photos, leave only footprints.” Lately, thanks to the confluence of user-friendly digital camera technology and the burgeoning interest in adventure travel, photographic excursions in search of wild game have ramped up into something of a growth industry.

Operators of these expeditions range from modest boutique firms to high-profile outfitters that send scores of clients and guides to destinations worldwide. Behind this legion of eager shutterbugs always lurks the potential for negative impacts on terrain and wildlife. One recent visitor to East Africa recalled a dismal cameo: a ring of off-road vehicles—open windows bristling with telephoto lenses—encircling an anxious cheetah that was crouching in the high grass to protect its kill.

Fortunately, most of the photo safari industry remains in the hands of responsible operators. They seem to function according to the collective credo that a camera is a tool for putting serious ecotravelers in close, minimally intrusive contact with the natural world.