Since Panasonic hasn't made any significant changes to the SW21's sensor or optics compared to the SW20, we weren't expecting any major differences in performance. In good lighting, it does a similarly adequate job reproducing colour saturation. But the level of detail is marginally better and there is less grain.
We also noticed a slight improvement in low light abilities, indicating that Panasonic has tweaked the image processing on this model compared to its predecessor. Unfortunately, performance in poor illumination is still not great. Although colour remains reasonably faithful, detail takes a nosedive. This will mean the SW21 won't be up to dark underwater shooting, such as in caverns or potholing, or possibly even down to its 2m limit.
The SW21 incorporates a mini-USB beneath one of its watertight covers. We didn't have any trouble editing the MPEG-2-based footage in any of the apps we tried. Alternatively, a proprietary connection is available for hooking the camcorder up to a TV via composite analogue video and stereo RCA audio.
Despite its low light limitations, it's hard not to like the Panasonic SDR-SW21. We were already impressed by its predecessor, and the new model has noticeably improved underwater protection, better looks, and slightly superior image quality. However, the most significant downside is the price. Consumer electronics have been getting more expensive across the board, thanks to the economic situation, but at over £100 more than its predecessor, the SW21 is close to HD camcorder territory. So even if it is the roughest, toughest camcorder out there, now you have to weigh that against whether you want to move up to HD instead.