Nathan Horton's business model is straightforward. A professional photographer, Horton helps amateur photographers take pictures abroad.
Photo tourism is an increasingly lucrative trade in Cambodia. Horton, who runs half-day jaunts in Phnom Penh and longer journeys into the provinces, is one of the practitioners capitalising on the trend.
"There is a massive growth of people who want to have a holiday and learn something at the same time, photography in particular," said Horton, who has done well in the seven years he's offered tours in Cambodia.
What started as $50 half-day trips around Phnom Penh now cost $80. To the more ambitious, Horton sells inclusive 10-day tours for $1,800.
"What I offer in Cambodia is a lot better than what I used to offer because I know the country so well now," he said. "I'm always afraid that [the prices] will frighten people off, and invariably it doesn't. Actually it attracts just as many people."
Taking pictures and travelling have always gone together, so creating a business out of it is a natural progression.
Mohan Gunti, a consultant to the Cambodia National Tourism Working Group, called tourism and photography "modern twins".
"Photo tourism is not yet considered an independent type of tourism, but it is becoming an en vogue product due to growing demands."
As president of the Cambodia Association of Travel Agents, Ang Kim Eang said local travel agencies should recognise the trend as a new revenue source.
Ang, who runs his own agency, Great Angkor Tours, is already profiting. Since May 2012, a Cambodian freelance photographer has led the excursions for Great Angkor.
"The more photography tours are offered, the more tourists will come," he said. "It will bring revenue and money into the economy and the tourism industry."
The trend, however, is not without potential downsides.
Cambodia has one of the worst records of tourism money trickling down to locals, Elizabeth Becker, author of Overbooked: The Exploding Business of Travel and Tourism, said in an email.
"When [photography tours are] done well, the tours can benefit the local economy by using local guides and patronising local establishments," said Becker, who covered Cambodia as a reporter for the Washington Post in the 1970s. She added that local elites and foreigners take an unusually high percentage of profits from tourism.
But photography outings can also serve as a window into a country, enriching the visitor's understanding of a different culture, she said.
"These tours are a good example of education morphing into tourism."
The rage for photography is taking place in tandem with a pivot towards "authentic" tourism, in which daily life, not just ancient temples, is the object of fascination.
Phnom Penh and Siem Reap are no longer the only hot spots. In Battambang, Banteay Meanchey, Pailin and Pursat provinces, tourism grew 67 per cent from 2011 to 2012, according government data.
Over the same time period, tourism in the better-known coastal provinces of Preah Sihanouk, Kampot, Kep, and Koh Kong grew only 45 per cent.
Images of everyday Cambodia that foreigners find novel are part of what fuels photography tours and tourism in general. In Cambodia, hardly anything escapes the hungry eye of the camera. During mass demonstrations against the ruling Cambodian People's Party earlier this month, tourists snapped photos of protests and barricades.
In a video that later popped up on social media, a group that appeared to be sightseeing crawled on hands and knees through a tangle of razor-wire, while friends on the other side recorded video of the manoeuvre. Memories!
Street vendors selling fried insects and other Western-unfamiliar treats on the riverside attract snap-happy tourists daily. But the attention can inadvertently annoy.
Triv Sreymao, 32, worries that a heavy camera presence scares off customers. Crowds of tourists sometimes block the stall.
"I don't mind when people take my photo," Triv said one recent evening, "But sometimes they interrupt my business."
As she talked, camera flashes lighted up baskets holding mounds of frogs, grasshoppers, crickets and worms.
Photography tourism works because few participants are in a rush. Less-avid photographers on a group tour may not want to linger long at a particular site. Bus drivers paid to drive from point A to point B aren't inclined to stop on the side of the road because the late-day light is just perfect.
But does it justify dropping almost two grand for a 10-day, organised tour?
Retired company director David Marsh seems to think so. At 68, he had traversed Cambodia's coastal provinces on his own. But as a keen photographer, he was looking for the tour that matched his hobby with his holiday. He found Horton's company online and booked the $1,800 package. By the end of June, he was seeing Cambodia through the lens of a Nikon D7000.
"The scope of the tour, with stopovers at several destinations and all accommodations pre-booked, seemed an excellent value," said Marsh in an email.
Horton has had difficulty keeping up with the demand. Until six months ago, he was a one-man business, reserving and confirming bookings, on top of guiding the tours. Now he's adding staff.
He isn't the only one.
"I'm getting more competition after seven years, but I think there's room for people to teach photography," he said.
ADDITIONAL REPORTING BY HOR KIMSAY