Keith, thank you for the input. I generally shoot in Manual mode only & any highlight optimisation is turned off. I see from the manual it is possible to adjust images on the camera so I might try that & see if it has any effect.
Could be that Canon DPP app handles the long exposure by using the ITU-R BT.709 conversion.
I ran a scan for ITU-R BT.709 in the /Applications dir & it showed up in /Canon Utilities/Canon MOV Encoder/ …….
also in /System dir
/Library/Extensions/NVDAResman.kext/Contents/MacOS/NVDAResman
./Library/Extensions/NVDAResmanG7xxx.kext/Contents/MacOS/NVDAResmanG7xxx
./Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vImage.framework /Versions/A/Headers/Transform.h
I think a simple short cut to resolving how Apple handles sYCC CR2 information is for someone to try out Final Cut Pro X & see if the problem occurs there.
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The following makes interesting reading :
http://lclevy.free.fr/cr2/
Canon CR2 specs
http://www.kenrockwell.com/tech/sycc.htm
Canon CR2 files sYCC
http://en.wikipedia.org/wiki/YCbCr
ITU-R BT.709 conversion
A different form of Y′CbCr is specified in the ITU-R BT.709 standard, primarily for HDTV use. The newer form is also used in some computer-display oriented applications. In this case, the values of Kb and Kr differ, but the formulas for using them are the same. For ITU-R BT.709, the constants are:
Kb = 0.0722
Kr = 0.2126
Out of interest here's the Exif
Aperture Value: 5.312
Color Space: sRGB
Components Configuration: 1, 2, 3, 0
Compressed Bits Per Pixel: 3
Custom Rendered: Normal process
Date Time Digitized: 2013:03:05 03:35:40
Date Time Original: 2013:03:05 03:35:40
Digital Zoom Ratio: 1
Exif Version: 2.3
Exposure Bias Value: 0
Exposure Mode: Manual exposure
Exposure Program: Manual
Exposure Time: 40
File Source: DSC
Flash: Flash did not fire, compulsory flash mode
FlashPix Version: 1.0
FNumber: 6.3
Focal Length: 17.505
Focal Plane Resolution Unit: inches
Focal Plane X Resolution: 5,905.021
Focal Plane Y Resolution: 5,902.351
ISO Speed Ratings: 800
Max Aperture Value: 3.625
Metering Mode: Pattern
Pixel X Dimension: 4,352
Pixel Y Dimension: 3,264
Scene Capture Type: Standard
Sensing Method: One-chip color area sensor
Shutter Speed Value: -5.312
White Balance: Auto white balance
AFInfo: 0.4100414, 0.4096201, 0.1799173, 0.1807598, n
Firmware: Firmware Version 1.00
Flash Compensation: 0
Focus Mode: 0
ImageStabilization: 259
Lens Info: 15.1, 60.4, 0, 0
Lens Model: 15.1-60.4 mm