If you're heading to the beach this winter, you might want to pack the Pentax
Optio W20 or the Olympus Stylus 720SW in your beach bag to capture your
On the video side, Pentax has a dedicated Underwater Movie mode, which again simply adds a blue cast. This may be fun for the pool, but skip it elsewhere. You're more likely to get good results with the basic movie mode instead. The Olympus only has one movie mode, but as the sample videos show, there was no shortage of blues in the water for either camera to pick up, and when the water is exceptionally clear, you will want this clarity reflected in your movies, as well.
Yes, PopPhoto.com is primarily interested in still photography performance, but we are weighing video performance much more heavily than usual in this head-to-head. Why?
Video provides a much more (bad pun alert) immersive experience of the underwater realm, and allows for capturing the movement and motion of shoals of small fish much better than single still images do, which are most often blurred because of the difficulty of achieving focus on small, speedy subjects that are very close to the camera (any camera, that is). Still underwater images offer a glimpse into another world, but video transports you there, providing motion, sounds, and a sense of being among the schools of fish, hovering over rocks and coral, and seeing a clown fish dart across the frame.
The Pentax Optio W20 outperforms the Olympus Stylus 720SW in video capture by a wide margin. The maximum video capture rate of the Olympus is slow and small by current standards: 320x240 pixels at 15 frames per second, with monaural sound. There is no zoom while recording, but you can record at any pre-selected focal length. The one advantage to the small and slow video mode is that it takes up significantly less memory to capture the scene to the xD memory card; but honestly, we'd rather pack a bigger memory card (or more small ones) and capture higher pixel-count video at a higher frame rate, because even at full image quality with no compression applied to the Olympus's video, fast motion can appear jagged and choppy.
The Pentax Optio W20 captures video at 640x480 pixels at 30 frames per second, producing bigger, smoother video capture. Like the Olympus, there is no zoom while recording, and audio is monaural via the built-in microphone. Video capture on the Pentax gobbles up free card space quickly, so if you plan to shoot tons of video on location, bring extra SD cards!
It should be mentioned that neither camera has great audio quality. You'll get a feel for the underwater world with the sound, but the calypso band at the resort won't sound all that great with either of these cameras.
Neither camera lights the world on fire in burst mode. The Olympus will fire off four shots in rapid succession (just over 1.5 seconds) without flash, before stalling. Even with the shutter button still depressed, that's it; it will not resume capture after buffering. It will also burst four shots with strobe, which slows it down considerably, to eight seconds total, focusing on a subject about three feet from the camera. There's also a High Speed Burst mode, which will fire off shots without strobe at a dizzying three frames per second for quite a long while; not as impressive a feat when you realize it is only capturing three megapixels!
Pentax also employs this resolution-dropping high-speed burst mode to capture six frames in just over two seconds before stalling out. Considering that both cameras are only utilizing about 40% of their available pixels, neither statistic is very impressive. Resolution-drop to increase burst rate falls into the same category as Digital Zoom -- a neat programming trick to boost performance on white paper spec sheets, but which lead to disappointing image quality results on photo paper.
At full 7-megapixel quality, the W20 will fire off shots continuously without strobe, at a rate of just about one image every two seconds until the card is filled. There is no burst mode with flash to speak of.
Are a handful of shots in rapid succession better than a ton of shots at a slower rate? We're on the fence as to which is better, as both can be useful depending on the situation.
In program mode, normal focus range, the Pentax Optio W20 is faster at achieving focus, and the Olympus feels sluggish even under ideal conditions. This is even more noticeable in lower light and in scenes lacking extremely dramatic contrast.
The Pentax also includes an interval shot mode, which can be set to record images at a set interval, from 10 seconds to 99 minutes, up to hundreds and hundreds of images, with an offset timer for when to begin shooting. For time-lapse imaging and videos, this is an excellent built-in feature. For compositing the shots into video, the capture resolution can be set to smaller pixel sizes, both to conserve memory card space, and because video does not require massive megapixels for screen display.