Pentax has introduced three new digital cameras: the five-megapixel Optio555, the 4.23-megapixel Optio S4 and the 3.2-megapixel Optio 33WR. All three models – due to ship next month – are compatible with Mac OS X and Mac OS 8.6-9.x, though some of the bundled software is Windows-only. A successor to the Optio550, the Optio555 sports a compact and lightweight design like its predecessor, but improves responsiveness, including reduced lag time so the camera is instantly ready when the power is turned on, according to Pentax. One touch of the playback button brings up recorded images; touch the shutter button and you return to shooting mode. The Optio555 has a 5x optical zoom (4x digital zoom for a combined 20x total zoom). The Optio555 also features PictBridge compatibility that eliminates the need for computer connectivity during printing by allowing the camera to be connected directly to a compatible printer. The Optio S4 comes with a 3x zoom lens and features such as a large manual-control playback button. It sports a sliding lens system that allows its 3x zoom lens to move up and away so the retracted lens is completely flush with the camera body. This system protects the lens and helps reduce the size. Features include a movie mode with sound playback, a voice-recording memo for attaching 30-second memos to select images, a 1.6-inch monitor and approximately 11MB of built-in memory. The Optio 33WR has a 2.8x zoom lens and a JIS Class 7 water resistance rating. Pentax says the digital camera remains watertight even when the camera is rinsed, splashed, or immersed in water. (In fact, the company will preview the digital camera submersed in a fish bowl at the Digital Focus media event on Monday, September 15, at the Metropolitan Pavilion in New York City during the PC Expo trade show.) Features include a movie mode with sound and voice memo, built-in flash, a 1.6-inch LCD monitor, an optical viewfinder, and a range of shooting modes. The Optio 33WR operates with an SD memory card or MultiMediaCard (MMC); power sources include two AA alkaline batteries or optional CR-V3 lithium batteries and AC adaptor. Pricing hasn’t yet been announced for the new digital cameras.