While the Canon EOS-1Ds Mark III's user interface is upgraded from the 1DsMark II, it is identical to that of the EOS-1D Mark III, including the arrangements on the LCD status displays.
See the Viewfinder tab above for info on and test results for the viewfinder, and the Live View tab for more on that mode.
Top LCD panel. The Top LCD panel is familiar, with slightly larger icons than the Mark II, and the addition of High and Low speed icons (H and L) for the two continuous capture modes, and an S for Single frame mode. A Mirror Lockup icon has been added, and the "# Personal Function" icon is now deleted. The new battery icon also has four bars, which Canon calls six modes, as indicated in the diagram above. The last two modes are flashing with one bar, and just flashing empty, at which point the camera usually stops working. (Illustration below courtesy Canon USA.)
Rear LCD panel. More changes are visible on the Rear LCD panel, due to the addition of an external media option (requires a WFT-E2A and a self-powered hard drive or other option). You can set just how to write to all three of the media types via the Function button and the Quick Control dial. Also new is the Wireless LAN connection icon and Data transfer icon that seems to indicate signal strength as well. Gone are the Blue/Amber and Green/Magenta white balance compensation indicators, in favor of a simple "WB +/-" icon. (Illustration below courtesy Canon USA.)
Record Mode. In record mode, pressing the INFO button displays current camera setting information on the main LCD. Most of this info is not available on the Top or Rear LCD panels.
See the illustration below (courtesy of Canon USA) for callouts on the default information display.
There is an alternate display which can be selected using a Custom function (C.Fn II-9), which shows the settings you would see on the top panel display, useful when it is difficult to see the other displays. While adjusting settings, the changes are reflected on the screen. When changing autofocus points, the focus point array is shown, and the selected focus point is highlighted in red. The animation at right shows the ISObeing changed, and then a new focus pointed selected.
Playback Mode. The Canon 1Ds Mark III by default shows each image as it's captured, though you can turn off this function through the Shooting menu. The display mode used in Record Review is the same as was last used in Playback mode, or you can hit the INFO button to cycle to a different mode. Likewise, in Playback mode, you can cycle between the available display options by pressing the INFO button repeatedly. The displays available are single image with basic information displayed on the top (the file number is displayed upper right, the shutter speed and aperture in the upper left), the same but with an overlay displaying image size/quality and and frame number, a detailed shooting info display with a luminance histogram, and a histogram display with RGB and luminance histograms.
If you press the Zoom Out button while viewing a single image on the LCD screen, it'll take you to a 4- and then a 9-image thumbnail display. You can also zoom in on an image, up to 10x at the highest resolution. The small navigator window in the lower right-hand corner shows you what part of the larger image you're currently viewing. The multi-controller lets you navigate around the full image, and the zoom in / zoom out keys increase or decrease the magnification level. You can also rotate, protect, erase, copy, and print images in playback mode, as well as add voice memos.