Sanyo has added higher resolution photos, better quality video and an improved face detection function to the DMX-CA8 - its latest waterproof Xacti digital still and movie camera.

The resolution of the image sensor in the DMX-CA8 has been increased from 6 megapixels on the old model to 8 megapixels. The top still image mode outputs a 4,000 pixel by 3,000 pixel resolution image (an effective 12-megapixel image created using pixel interpolation).

The sensor has also been switched from a CCD (charge couple device) image sensor to one based on a CMOS (complementary metal-oxide semiconductor) production process.

While that sounds like a change that only engineers would care about it has an impact on the camera's video function. CMOS sensors can work faster than CCD, allowing Sanyo to increase the frame rate on the top-quality video mode from 30 frames per second to 60 frames per second. That should mean smoother video when played at normal speed or slow motion.

The TV-HR mode, the highest of five video shooting modes, produces a VGA resolution (640 pixels by 480 pixels) image at 60 frames per second and a bit rate of 6Mbps. The camera uses MPEG4 AVC/H.264 compression for the video files.

Sanyo has also improved the face detection function, which can keep track of up to four people in a shot and attempt to keep them in focus and well exposed, so that it works with video as well as still images.

The function also works underwater and can track people wearing all but the largest snorkelling or diving masks, said Sanyo. It's waterproof at a depth of around 1.5 metres, which means it should work well for snorkelling but not for scuba diving.

Sanyo Xacti DMX-CA8

Other features of the camera include a digital image stabiliser, 5x optical zoom lens and an SD Card memory card slot. It measures 70mm by 111 mm by 40 mm and weighs 239g. The battery should provide enough power for 205 still image shots or about 75 minutes of continuous video shooting.

The DMX-CA8 will go on sale in Japan in mid-May for about ¥50,000 (£245). It will arrive in other markets around the world later, although precise dates haven't been fixed.