Ahead of the announcement, the ABC contacted 10 of the 49 finalists, and asked them to share the stories behind their photographs.
Of the above picture, titled A Moment, photographer Millie Brown said it captured a brief, captivating look from a child playing by the sea in East Arnhem Land.
"[It was] a very organic, brief moment in time where I asked him to look down the lens, and he did, and he gave me that very strong, intense look," she said.
"Then he slipped straight back into the running and the jumping and the diving and the swimming."
Brad 'Gaggsy' Gallagher at a bachelor and spinsters ball, Toorandin, Victoria by Ingvar Kenne
Brad 'Gaggsy' Gallagher was spotted by photographer Ingvar Kenne, who was shooting a series on B&S balls.
"I find [B&S balls] fascinating, though not my scene particularly," Kenne said. "I just came across him in the course of walking this really big showground where it took place," he said.
"It's a very quick process ... I just asked him to be direct with me and look back at me."
Kuei - The Sea of Gazelles - South Sudan to Oz by Kellie Maree Leczinska
This image of a woman who settled in Australia after fleeing civil war in South Sudan and spending eight years in a UN refugee camp happened almost by accident, photographer Kellie Maree Leczinska said.
"It wasn't planned — I actually photographed her for another body of work ... I started to photograph her and asked her a little bit about herself, and this story came out," she said.
"It was just an incredible story of this beautiful, elegant woman who has endured the most terrible situations.
"When we think of UN refugee camps we think it's going to be a place of sanctuary, but it's not like that at all."
Leczinska said she found the image resembled classic portraiture
"In some respects she looks like she's coming out of darkness," she said.
"I thought it had a bit of a Girl With a Pearl Earring look about it."
Cameron and the prosthetic arm by Steve Wise
Medical photographer Steve Wise's portrait of his son's friend Cameron was inspired by a prosthetic limb lent to him by colleagues.
"The assumption's going to be there that he's a young man with just one arm, but really the primary thing for the portrait was to show off that prosthetic," he said.
"He actually does have use of both arms.
"He's actually quite a fit young sportsman, and the big kicker of the portrait for me was the expression on his face.
"I said 'Cam, I know you're a sportsman, your right arm's your main arm for footy and cricket. Just imagine you didn't have it, mate — you had this prosthetic instead'.
"His face sort of took on this really hard to read expression."
Luke and Nacoya by Daniel Sponiar
Photographer Daniel Sponiar aimed for a less produced, more "authentic" portrait when he shot this image of heavy metal musician Luke with his dog Nacoya.
"I got in touch with a makeup artist friend of mine and I said to her 'I've got this idea for a portrait, do you know anyone who's got a beard and heaps tattoos and some kind of furry dog that wouldn't mind getting their clothes off?' And she was like, 'Yeah, my mate Luke' straight away," Sponiar said.
"I didn't take it for anything particular at the time.
"As a heavy metal singer and guitarist he was kind of juxtaposed by this Pomeranian. You think a guy in a heavy metal band is going to have a staffy or some kind of bulldog.
"He was quite a sensitive guy."
Return by Philip Myers
Photographer Philip Myers likes that his picture of actor Tom E. Lewis shows a man reconnecting to his land with strength and integrity.
"I like the fact that he connects well with the viewer. There's a directness. There's a confidence. It was taken quite early in the morning, so it's quite surprising to have that response," he said.
Working on a documentary following Lewis in Arnhem Land, Meyers took the opportunity to capture the actor's journey to his ancestral home in his images.
"He was returning from looking for his island, and I ran into the water and started photographing him just as he had got off the boat and was returning on shore," Myers said.
"He's confident and proud, and I think that's all a part of that reconnection with his land, and that spiritual journey that he was on."
Portrait of a young Aussie, Matuse Peace by John McRae
This photograph of young Australian Matuse Peace is in many ways a traditional portrait, photographer John McRae said.
"On top of that, I've been investigating the idea of prejudice and stereotyping," he said.
"The guy's from a Lebanese Muslim background, but he's basically an Aussie ... he goes around in jeans and a t-shirt like any other young Aussie.
"But I imposed, if you like, Arab costume onto this person."
McRae said the portrait aimed to show the illogical nature of racial stereotyping.
"What I've done is kind of, in a stupid way, imposed that stereotype onto that guy, who just happens to be of Lebanese descent and identifies at Muslim," he said.
"In spite of what I've done to the guy, and what I imposed on his image, he remains an honest young Aussie."
Richard Morecroft & Alison Mackay by Gary Grealy
Gary Grealy said he hoped his "stately" portrait of former ABC journalist Richard Morecroft and his partner, artist Alison Mackay, captured the pair's relationship.
"They are the warmest couple, they make you feel so incredibly welcome," he said.
"There is this relationship where they write together for magazines, they work independently of each other, but they work together. So it's a relationship not only of a couple, a unit together, but that translates over to their work as well."
"It's part of an ongoing series ... all of my work relates to the art world."
The skin I'm in II by Brian Cassey
It took a reflection period of six years for photographer Brian Cassey to work up the courage to ask burns survivor Carol Mayer for another chance to capture her peaceful image.
"I was asked by the Sunday Mail newspaper to do a portrait of Carol, and at the time I took a very tight face portrait of her," he said.
"I started thinking afterwards, and had this idea for a photo set, which included The Skin I'm In II, but I didn't have the courage to ask her at the time."
With the idea eating away at Cassey, he eventually asked Mayer for the opportunity to photograph her again.
"She feels that it will empower other burns victims and gives them the confidence to do things they wouldn't normally do because of their injuries," he said.
"There's a serenity [in the image]. She's at peace with the 'skin I'm in'."
Ninety-nine-and-three-quarters by Nic Duncan
When Nic Duncan was referred to photograph now 100-year-old Nell, who still lives in her own home, and remains an active member of the community, she found a zest for life few at that age still possess.
"She's a real character, so I really just wanted to capture her personality, and the fact she lifted the magnifying glass up to her face was unexpected. Fortunately I was ready for it," Duncan said.
"She's got a very devious playful side to her. She's always got a twinkle in her eye."