Sony didn't so much enter the market for small and thin digital still cameras as break down the door today when it unveiled a camera measuring about the same size as a pack of playing cards.

The company claims its camera is the smallest 5Mp (megapixel) model currently available. Small-format cameras are also appearing from Casio, Konica and Pentax.

Tall and thin, the DSC-T1 camera boasts a 2.5in LCD (liquid crystal display) monitor as well as a Carl Zeiss lens with a 3x optical zoom.

Rather than protruding from the camera like most zoom lenses, however, the lens is mounted sideways so that it's already extended inside the body of the camera. A prism is used to reflect light so that the lens can see ahead.

This setup is gaining favour among designers of small cameras because it helps keep the casing thin and cuts down on both startup time and noise.

The maximum resolution available from the camera is 2,592x1,944 pixels and there are four additional resolution settings. It can also record Mpeg-1 format video and audio at 640x480 pixel (VGA) resolution at 30 frames per second. Other features include a USB 2.0 interface and support for Memory Stick Duo and Memory Stick Pro Duo memory cards.

The camera measures 91x60x21mm and weighs 180g with a memory card and battery inserted.

The DSC-T1 will be available in the US in January for around $550 (£325) but UK details have not yet been disclosed.