Since Canon and only Canon can handle the file (as best we know), I suspect they have baked something into the RAW that violates their own file definition, and have written their own RAW converters to handle this but have not shared it. Since this happens with exposures longer than some still un-specific duration, I would look for an in-camera setting that affects long exposures. Does your camera have any? The one that comes to mind is some kind of automatic noise reduction for long exposures.
Other than that nothing comes to mind. Sorry.
Thank you for responding so quickly & your suggestions therein. I apologise for the delay but I have been trying to get some scope on this problem.
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
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.
The following makes interesting reading :
Canon CR2 specs
Canon CR2 files sYCC
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
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
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
Lens Info: 15.1, 60.4, 0, 0
Lens Model: 15.1-60.4 mm