I opted to pull the trigger and acquire this much anticipated software. At first glance, it can be a bit overwhelming in printing targets, lining up the camera so the targets are precise, installing software on a laptop (not a desktop) as you will more than likely need space to roam especially with Tele's zooms . There are many things to keep in mind when setting up for this calibration though the software does a good job of pointing most of those out.
I noted however the software did a few unusual things to at least my 5D that weren't there before. For one, the shutter release was reprogrammed to perform a different function other than to focus. I found this out when I tried to focus on the printed chart and lost all AF capabilities. I swapped out the 24-105 lens with a 100mm 2.8 L and nothing (still no focus). I put the 24-105 on my 7D and it was fine so I had isolated it was in fact the 5D. I then checked Custom Controls and found the 5D M3 was reprogrammed. I also noted Spot Metering kept getting turned on as well as the Exposure was up by a +1. On a few occasions I also found Custom White Balance toggled on and not AWB. The printed 8.5 x 11 FoCal chart did not work with the 16-35mm 2.8 MK II lens. It just simply wouldn't focus at 1 foot (MFD is .92 feet) or 5 feet which is perhaps due to the target being too small? Not sure. I ran the Aperture sharpness tests on the same lens (the 100mm 2.8 L) consecutively twice and got different results. The camera nor the light did not change. The first time is showed the 7.1 was the sharpest aperture then it showed on a second run that 4.5 was the sharpest aperture. One would think it would be consistent - same test same camera, same lens.
Any one else have any comments on this or own this software with the 5D Mark III? PS I found the Martin Bailey site had it on a promo for £45 British pounds or $73 US vs £69.95 or $112.21 USD.
PS I did see the blurb on the web site: "Does FoCal change my camera settings?"
"FoCal changes a number of settings on the camera while running the test (e.g. aperture, ISO, metering etc.). Before each test is run, the current settings of the camera are stored on the computer. When the test completes, the settings are restored so your camera is back exactly as you had it before running the test.
Should anything go wrong (e.g. a power cut, the camera battery running out, the cable being unplugged etc.), the next time FoCal is run with the camera connected it will offer to restore the settings exactly as they were."
The camera was not reset hence the documenting of the above issues. Perhaps this is specific to the 5D MK 3