From Canon USA's site:
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EOS 5D Mark III Digital SLR Camera
EOS-1D X Digital SLR Camera
Depending upon the shooting conditions, it may take slightly longer for the EOS 5D Mark III and EOS-1D X digital SLR cameras to acquire focus when using the Speedlite's AF Assist Beam, compared with that of the EOS 5D Mark II and EOS-1D Mark IV digital SLR cameras using the Speedlite's AF Assist Beam.
We are developing a solution to enhance the focusing feature for the EOS 5D Mark III and EOS-1D X and plan to release a firmware update based on following estimated schedule:
EOS 5D Mark III: (estimated) Late April, 2013
EOS-1D X: (estimated) Late May, 2013
First, it was f/8 AF then the clean HDMI out. Canon has also said they will update the AF-Assist issue, but it came later, and will likely be rolled up in a furure update.
So this update does not address the issue with AF-assist beam lag. Is that a separate update?
I was wondering this myself as the Canon website does not specifically mention this. I thought that this was one of the big driving issues for a firmware update so I find it odd it's not in included.
Absolutely. However, the confusion comes from the Canon USA press release which does not mention the AF assist issue.
"New Firmware Update For Canon EOS 5D Mark III Digital SLR Camera Provides Uncompressed HDMI Output Support And Improved AF Performance
LAKE SUCCESS, N.Y., October 23, 2012 – Canon U.S.A., Inc., a leader in digital imaging solutions, today announced a new firmware update for the EOS 5D Mark III Digital SLR camera that significantly improves the camera's performance and usability. In response to requests from professionals working in the fields of cinema and television production, the firmware update enables the use of uncompressed HDMI Output support, making possible more efficient video editing and monitoring procedures. Additionally, the upgrade supports the advanced needs of photographers through improved AF performance when capturing still images.
Uncompressed HDMI Output Support
When shooting video, HDMI Output makes possible the recording of high-definition uncompressed video data (YCbCr 4:2:2, 8 bit) from the EOS 5D Mark III to an external recorder via the camera's HDMI terminal. This, in turn, facilitates the editing of video data with minimal image degradation for greater on-site workflow efficiency during motion picture and video productions. Additionally, video being captured can be displayed on an external monitor, enabling real-time, on-site monitoring of high-definition video during shooting.
Improved AF Functionality
Even when the EOS 5D Mark III is equipped with an extender and lens making possible a maximum aperture of f/8, the firmware update supports AF employing the camera's central cross-type points (currently compatible with maximum apertures up to f/5.6). Accordingly, the update will allow users to take advantage of AF when shooting distant subjects, benefitting sports and nature photographers, particularly when using telephoto lenses.
The new firmware update will be available, at no charge, in April 2013 from the Canon U.S.A. website and can be downloaded by end users or through Canon Factory Service Centers"
I just find it odd that it's left out of the press release since such a big deal was made of it.