Judging from many of the emails I receive asking for advice about buying cameras, there are a lot of you out there who would like the controllability and image quality of a digital SLR, but don't want the bulk and weight of a big camera system. Up until now this has meant choosing either a high-end compact like the Panasonic LX3 or Canon G10, or a super-zoom bridge camera such as the Panasonic FZ28 or Nikon P80.
While these are all capable cameras, they don't really come close to the kind of image quality produced by a digital SLR, mostly because they all have small compact-camera sensors, so buyers have had to compromise image quality for portability. All of that could be about to change though, because Panasonic has launched a camera that fills the gap between high-end compact cameras and full-sized DSLRs. It's called the Lumix G1, and it's an entirely new kind of digital camera.
Existing digital SLRs are large and complex devices. Even nine years after the launch of the first "consumer" digital SLR the majority of them are still based on the design of previous 35mm film cameras. In most cases this is so that owners of film SLRs can still use their existing lenses and accessories, thus ensuring brand loyalty, but even the Olympus E-system, with its designed-for-digital smaller lens mount, still uses film SLR technology.
The optical layout inside an SLR camera hasn't changed much in 30 years. Light comes in via the lens and strikes the reflex mirror, where it is split into different paths for the viewfinder, autofocus sensor and exposure meter. When the shutter is triggered the reflex mirror flips up out of the way allowing light onto the film or sensor.
What Panasonic has done with the G1 is to re-think the insides of the camera. They've got rid of that bulky, heavy and noisy reflex mirror, and with it the optical viewfinder, and replaced it with a simple system like the insides of a digital compact, with an electronic viewfinder and live LCD monitor. However they've kept the large DSLR sensor; the G1 uses the same size Four Thirds sensor as the Olympus E-system and the L10 DSLR.