see also:

• Micro Four Thirds system
• a catalogue of Micro Four Thirds lenses
• comparison of current Micro Four Thirds cameras
• mirrorless camera systems
• professional level digital video cameras
• Pansonic US website GH-3 specs

this video shot with a pre-production GH-3 and promoted on Philip Bloom's blog is awesome:

demonstration of the smartphone app to wirelessly remote control the camera and view the live view feed

• the Panasonic GH-3 Micro Four Thirds camera was formerly announced in Sept 2012
• it is designed to be a semi-pro camera aimed at indy videographers in particular
• it offers the best features for video of all the current mirrorless camera systems and digital SLR cameras, presumably thanks in part to the video hacker Vitaly who has been advising Panasonic
• it is a substantial upgrade to the Panasonic GH-2 camera:
  • bigger, heavier with a more substantial grip
  • magnesium allow stronger frame
  • weatherproofed
  • semi-pro video features
  • faster AF and processing
  • 6fps instead of 5fps
  • OLED rear screen instead of LCD
  • improved low pass filter
  • improved image processing engine
  • additional control dial and 2 extra Fn buttons
  • intervalometer
  • improved user interface
  • optional vertical grip
  • wireless TTL flash - the 1st time in any Panasonic camera - I just hope it is compatible with Olympus flashes - I would think this likely as the Panasonic flash looks like it could be a re-badged Olympus FL600R flash!
  • HDR mode
  • electronic shutter
  • PC sync port
  • iOS and Android app WiFi remote control
  • WiFi instant image transfer
  • live HDMI out of video
  • BUT NO oversized sensor for uncropped 16:9 images and no 4mp 40fps cropped mode (only 20fps)
    • the GH-2 could shoot: 4:3 4608×3456 (15.9mp) 3:2 4752×3168 (15mp) and 16:9 4976×2800 (13.9mp)
    • the GH-3 can only shoot: 4:3 4608×3456 (15.9mp) 3:2 4608×3072 (14.2mp) and 16:9 4608×2592 (11.9mp) - ie. 3:2 and 16:9 are just cropped versions of 4:3, not extra-wide images as with GH-1 and GH-2
    • for comparison the 18mp APS-C Canon cameras can shoot: 4:3 4608×3456 (15.9mp); 3:2 5184 x 3456 (17.9mp); 16:9 5184 x 2912 (15mp)
  • seems to have more moire artefacts but only on fine horizontal structures unlike most dSLRs which have much more moire

• 16mp Live MOS sensor - but NOT over-sized to allow native 16:9 images such as with the GH-1 and GH-2
• 6fps burst rate (20fps crop mode; 4fps live view mode)
• ISO 125-25,600 extended range
• new 16:9 1,744k dot OLED EVF with 8x faster data transfer to it for smoother display on panning
• eye-sensor EVF-rear screen auto-switching
• 3.0-inch 614K-dot free-angle OLED rear monitor (3:2 aspect) rotates 180° to the side and tilts 270° up and down for around 100% field of view and uses static touch control
• much larger than the GH-2 – more dSLR-like in size
• weatherproofed
• designed for pro-videographers in particular
• fast AF
• three-core Venus 7 FHD engine
• 3D Noise Reduction (3DNR)
• Multiprocess Noise Reduction (MNR)
• swivel, rotate, articulated touch screen
• built-in popup flash
• wireless TTL flash with DMW-FL360L flash
• PC sync socket
• iOS and Android app control via WiFi (built-in)
• .MOV and AVCHD video formats with Timecode support (not available in MP4 mode)
• 60p/50p/30p/25p/24p HD H.264 video:
  • IPB .MOV: 50Mbps 60/50/30/25/24p
  • All-I .MOV: 72Mbps in 30/25/24p
  • AVCHD format: 28Mbps 60/50p; 24Mbps 60/50i/24p;
  • MP4 format: 20Mbps 30/25p
• video exposure modes: Program AE / Aperture-Priority / Sutter-Priority / Manual Exposure
• 40%, 48%, 80% Slow Motion Video
• video count-up system with Rec Run and Free Run codes and a recording system with Drop Frame and Non Drop Frame codes
• heat-dispersing design for higher image quality in extended shooting
• stereo mic plus 3.5mm mic socket and 3.5mm headphone socket (can also choose “processed” audio to listen but with slight audio delay)
• WiFi instant image transfer
  • save photos to the Panasonic exclusive cloud service LUMIX CLUB
  • easily transfer images to Facebook™, Flickr™, Picasa™, Twitter™ or YouTube™
  • play back images on DLNA (Digital Living Network Alliance) -compliant AV equipment via a wireless router at home
• live HDMI out of video at 4:2:0, 8 bit
• manual focus peaking was rumoured but does not appear to be in the pre-release firmware yet
• shutter 60sec – 1/4000th sec, flash sync only 1/160th sec though
• HDR mode
• electronic shutter of both front and rear curtain
• new Tough extended shooting time battery
• SD card slot supports UHS-I high-speed data transfer standard
• optional vertical grip
• 550g
• RRP $US1299

• EOSHD - from a videographer's point of view
• dpreview.com
• Zacuto videography viewpoint and a multitude of Zacuto accessories

• ePhotozine review
• EOSHD.com's review of a pre-production model Nov 2012
• camera labs review