Ready for this? Olympus and Panasonic just announced a new mirrorless format and lens mount based on the venerable Four Thirds standard. Dubbed Micro Four Thirds System, the enhanced standard uses the same 18 x 13.5-mm sensor but promises 50% slimmer cameras due to the removal of the mirror box. We're also looking at smaller lenses (while remaining compatible with existing Four Third lenses with an adapter) thanks in part to a new reduced lens mount which is now 6-mm smaller. With the mirror box gone, Micro Four Third cameras will lose the optical viewfinder so you'll have to frame up your subjects using a Live View LCD or an external viewfinder.

How big of a development is this? Huge. As Phil Askey, editor over at dpreview puts it, "This is without doubt the most exciting digital photography announcement this year. It's fair to say that this "extension / addition" to the Four Thirds standard is finally able to deliver on the original promise of that format; considerably smaller and lighter lenses and bodies."

Unfortunately, no products were announced so you've got plenty of time to debate the spec and pore over the illustrations we've dropped in after the break.

[Via 1001 Noisy Cameras]