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

In the new camera, called the DMX-CA8, the resolution of the image sensor has been increased from 6 megapixels on the old model to 8 megapixels. The top still image mode outputs a 4,000-x-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 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 6M bps (bits per second). 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 snorkeling or diving masks, said Sanyo. It's waterproof at a depth of around 1.5 meters, which means it should work well for snorkeling but not for scuba diving.

Other features of the camera include a digital image stabilizer, 5x optical zoom lens and SD Card memory card slot. It measures 70-x-111-x-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.