"The job is getting harder and harder because there is quite a build-up of deer in Fiordland now and the forest is opening up, which creates more trails to choose from.
"It's becoming harder to know where to put the cameras. Sometimes it's difficult enough to decide which side of a tree to put one on.
"I was tempted to flag the mission, but we know far too much about the animal and the use of cameras to give it away so easily."
He said his main motivation for continuing was the addictive thrill of the chase and the fear of regret.
"I'd hate to end up in an old folks' home thinking, 'Gosh, if only we had just done it for one more season'.
"You get the feeling that the next time you go, that it will be the time you get the frame. It would be a shame to give it away now."
Mr Tustin said he had received sponsorship to buy new cameras, BF-7s made by Canadian manufacturer Spypoint, which are much more compact and durable.
The cameras were powered by six AA batteries, provided better-quality digital photographs, could hold more photographs and had a better trigger distance, he said.
"They also have black flash which is invisible - the animals won't even know they've been photographed."
He hoped to install them early next month, again on animal trails.
The last known photographs of moose in Fiordland were taken by Fred Stewardson, of Hikurangi, who took the pictures on a hunting trip to Wet Jacket Arm in 1953.
His older hunting companion, friend and mentor Eddie Young, swore him to secrecy for many years, fearing the moose would be shot by hunters if the photographs were revealed at the time.
Only a handful of photographs of moose in Fiordland are known to exist, most taken between 1923 and 1952.
- Otago Daily Times