A radical camera that lets users adjust the focus after taking pictures will be available in October at shops in Australia, Canada, Singapore, Hong Kong and the United States.

The move announced on Tuesday marked an expansion for the Lytro, which began shipping in March but has been available only by order on the Internet.

"Since introducing the Lytro camera just six months ago, nearly 400,000 light field pictures have been shared on Lytro.com," said Lytro chief executive Charles Chi.

"We are excited to take this picture revolution one step further by making Lytro available to more photographers in the US and around the world."

The Lytro is the creation of Ren Ng, who started work on the digital camera while studying for a doctorate in computer science at Stanford University in California.

The telescope-shaped camera uses what is known as "light field technology" to allow the focal point of a digital image to be changed after the picture is taken, a feature that Lytro calls "shoot now, focus later."

Clicking on a Lytro picture displayed on a computer screen allows a viewer to shift the focus from a subject in the foreground, for example, to a subject in the background.

The Lytro can do this because it uses powerful sensors to capture significantly more light than a conventional camera.

Lytro executive chairman Ng, who was born in Malaysia and raised in Australia, describes the images as "living pictures" because of the ability to manipulate them.

When Lytro pictures are shared online, the "light field engine" travels with each image so anyone can change focal points as desired.

The 16-gigabyte model of the camera, which is about the same size as a stick of butter and can fit easily in a pocket, costs $499 and can hold 750 pictures. An 8GB version costs $399 and can capture 350 images.

Lytro said that expanding availability of the cameras come as demand increases for the technology around the world.

"Australians are asking for the Lytro camera and we're excited to bring it to them," said Dan Miall of Blonde Robot, with is distributing the cameras in that country.

"There has been a lot of excitement to be a part of this next phase in photography and start producing light field pictures in Australia."