Dusseldorf Museum of Art #4
Because LUMIX GH1's auto focus is achieved by contrast control on the sensor, it can allow its owner to focus on the moving object while shooting a video. This is a new feature for a prosumer digicam, since neither Canon 5D II nor Nikon D90, the two current video recording SLRs, can do it. Obviously, this all needs to be happening in the 720 mode, if we want to retain good control over the quality of the video picture.
It is important to compare the sizes of the sensors. This is where Lumix GH1 lets us down a bit, because its sensor is only 17.3 x 13mm, while Nikon D90 is in the middle with 23.6 x 15.8mm and Canon 5D is clear winner with 23.6 x 15.8mm. As sensors go, larger is definitely better, since bigger sensors give better low light performance.