Brian Yen got his big break on a day out with his daughter at Ocean Park. On the Hong Kong amusement park's Ocean Express, a five-minute train ride during which the lights dim and the overhead monitor displays underwater animals, he saw a woman staring at her glowing phone in the middle of the packed carriage.

"I noticed her standing there, so I raised my arms and took a couple of shots in that direction," he says. "It took a few tries to get it right."

The stay-at-home dad entered A Node Glows in the Dark in the National Geographic Photo Contest 2014.

"One morning I got an email telling me I'd won [the grand prize]," Yen says. "Growing up, being a National Geographic photographer was a romantic ideal for me, so I was super happy. It's unbelievable, and I'm sure there was a lot of luck involved."

Taiwan-born Yen won US$10,000 and a four-day trip to the National Geographic headquarters, in Washington, in the United States. He toured the magazine's archive room, which contains more than a million images, and met world renowned photographers Steve McCurry (best known for his portrait of "Afghan girl") and David Doubilet.

A former investor in tech start-ups in Silicon Valley, Yen rediscovered his passion for photography after moving to Hong Kong 10 years ago. His work has since been published in The Washington Post, National Geographic and on the blog My Modern Met.

Nevertheless, Yen insists that, for him, photography is an art, not a vocation. He openly shares his photographs on his public Flickr stream, and keeps a relatively low profile - he politely declines to have his photograph taken for this article.

"I want people to recognise my photography, not my name or my face," he says.

Yen began taking pictures in the 1970s, as a teenager, shooting on an old rangefinder camera. Today, he mainly shoots with either a Canon 1Ds Mark III or a Sony RX100 Mark III, but also uses the camera on his iPhone.

"I think that camera equipment doesn't matter very much," he says. "If you are a good photographer, all you need is a pinhole."

Once a year, Yen travels to the Philippines as a volunteer for the International Care Ministries, to photograph a poor family. He donates one shot from the trip for auction and the money it raises is used to help the family in the picture.

"I try to present poverty with a lot of hope, not sadness," he says. "I want to focus on how people can improve."

To see more of Yen's work, go to www.flickr.com/photos/briyen.