Items range from full-plated box cameras on tripods made before the turn of last century, to examples of the first handheld cameras, early instamatics and polaroid cameras - all the rage in the late 1980s-right through to rare examples of hybrid cameras that can take both film and digital images, as well as a bulky aerial mapping cameras and projectors.
Notable pieces on display include a Voigtlander lens built in 1860 for a an early plate camera, one of Kodak's first hand-held cameras made in 1888, a gold-plated camera created by Leica for the 1936 Berlin Olympics bearing the Nazi Party crest, and even a camera reputedly owned by Hitler's right hand man, Rudolf Hess.
Mr Trevelyan said the early Kodak hand-held cameras cost the equivalent of eight weeks' wages, and developing the film was nearly as expensive.
"You'd have to send it George Eastman [Kodak's founder] and he would return it with a new roll of film for $10 - the equivalent of three weeks of wages," he said.
Mr Trevelyan received his first camera at age 11 back in 1958 and has collected many of his cameras while on shore leave from his decades working on and managing oil rigs around the world.
A lot of his collection was devoted to his three favourite German camera makers: Leica, Voigtlander and Zeiss-Contax.
"Leica are like the Rolls-Royce or Rolexes of cameras - they are perfect," he said.
Mr Trevelyan said he owned replicas of cameras that had sold for millions of dollars at auction, and had spent thousands on some individual items in his collection.
But his rarer pieces were so easily identifiable he said they would not be worth stealing - even if criminals could get past the alarm system and the bars on the windows of the old bank building.
"Unless they know where to sell them, they are not really worth anything to anyone," said Mr Trevelyan, who will also be living upstairs in a flat above the museum as a precaution.
Mr Trevelyan said his museum would appeal mainly to fellow collectors and photography enthusiasts - and perhaps some older, more nostalgic camera owners.
"I expect most people under the age of 25 are just going to come in and say 'pfftt' and walk out again - they are not going to be interested at all."
Mr Trevelyan said he intended to charge an entry fee for people to visit the museum, which would be open over Labour Weekend for Waipukurau's 150th anniversary celebrations.
Beyond that he did not expect to open all the time but would instead take group bookings and school visits by appointment by calling 021 2121611, he said.