Casio revealed their ultra-compact EXILIM EX-Z3 at CES 2003 in January. The EX-Z3 is the first Casio digital camera to carry the EXILIM name and have an optical zoom lens. The ultra-slim profile is partially thanks to the use of the same sliding lens design as seen in the Optio S. The join alliance between Pentax and Casio doesn't end there however, Casio provide Pentax with LSI chips and operating software for the Optio S, thus both companies benefit. The EX-Z3 has a three megapixel sensor, lightweight Lithium-Ion rechargeable battery and stores images on SD / MMC cards.

Pentax sliding lens design

Lens at power off, note that three elements slide upwards out of imaging path thus a thin profile can be maintained
Lens at wide angle (elements back in the image path)
Lens at telephoto