The key feature of the GH1 is of course its video recording capability, and it's fairly obvious that Panasonic has put a lot of thought into it. While most digital cameras with so-called HD video recording are only capable of 1280 x 720 pixel resolution, the GH1 can shoot at a full HD resolution of 1920 x 1080 pixels at 25 frames per second, or 1280 x 720 at an ultra-smooth 50fps.
Video files are encoded in either Motion JPEG or AVCHD formats, recording directly onto an SD memory card. Motion JPEG is a good universal standard, ideal for video editing on a home PC, or for sharing via email. The AVCHD format is much better quality when played back on a TV, but requires special software for editing. The GH1 has an HDMI socket for connection to a suitably equipped TV, and has a special Viera Link, so if you have a Panasonic HD TV the camera can be operated via the TV remote control.
The video mode on the GH1 is far more comprehensively implemented than the video functions of most compact cameras. As well as the usual default fully automatic mode it also has a full manual mode, in which both shutter speed and aperture can be adjusted, and spot, centre-weighted or multi-zone light metering modes can be selected. Sound recording is also more sophisticated than usual. The twin built-in microphones has an optional wind-cut feature, which goes some way towards filtering out wind noise on the soundtrack. As well as the built-in microphones the GH1 also has a socket to plug in an external stereo microphone. A purpose-built boom microphone which clips into the flash hotshoe is supposed to be available, although it's hard to find anyone who's selling it.
There's no doubt at all that the GH1 is technically a very capable video camera. At the press launch I was shown a short film made by a professional film maker, shot entirely on the GH1, and the results were very certainly very impressive. However having used it to shoot video myself, I have some comments about this feature. First, I doubt that a professional film maker, or even a keen amateur, is going to choose a GH1 over any of the very capable and significantly cheaper HD camcorders that are widely available.
For anyone else the HD video feature is just going to be an added bonus that might be used occasionally, and for that it's simply not worth the cost. The standard Lumix G1 is currently selling for under £450 including a 14-45mm zoom lens, which is actually pretty good value for money. It's hard to justify spending nearly three times as much for a bonus novelty feature you're not going to use that much.
My second point about hybrid video/stills cameras is that they're never going to work satisfactorily. If you look at the way the ergonomics of the typical video camcorder has evolved, the body is designed to rest on the flat palm of the right hand with the forearm vertical, a grip that is well suited to panning the camera smoothly in the horizontal plane, and all the main shooting controls are accessible with the minimum of hand movement, so that you don't cause camera shake when filming.
By contrast a digital SLR is designed to be held in both hands, gripped tight into the chest for maximum stability when shooting stills. The controls are not designed with stability or shake reduction in mind, because they don't have to be. My point is that the body shape and control layout of a typical DSLR is fundamentally unsuited to hand-held video shooting, and I really don't believe that any sort of successful hybrid is even possible using current camera forms. The GH1 is as close as it's possible to get, and is certainly capable of producing excellent results, but you can get better results for less from a dedicated camcorder.