CR2 maker note

The Exif tag MakerNote (0x927C) in IFD 0’s Exif IFD holds Canon’s own data. It is a TIFF IFD with no header of its own: a count of entries, the 12-byte entries, and a next-IFD offset, with offsets counted from the start of the TIFF file. Canon has not published it; the names below are ExifTool’s, from years of reverse engineering. The same maker note is used in Canon JPEGs and in CR3’s CMT3 box.

Main tags

Many tags are arrays of shorts whose meaning ExifTool documents index by index.

Tag	Name	Content
`0x0001`	CameraSettings	Array: macro mode, self-timer, quality, flash mode, drive mode, focus mode, image size, exposure mode, lens type, focal lengths, aperture limits and more
`0x0002`	FocalLength	Array: focal type, focal length, focal plane sizes
`0x0003`	FlashInfo	Unknown
`0x0004`	ShotInfo	Array: ISO, measured exposure, target aperture and shutter speed, white balance, sequence number, flash output and more
`0x0005`	Panorama	Panorama frame and direction
`0x0006`	ImageType	Text, such as “Canon EOS 5D Mark II”
`0x0007`	FirmwareVersion	Text
`0x0008`	FileNumber	Long
`0x0009`	OwnerName	Text
`0x000C`	SerialNumber	Long
`0x000D`	CameraInfo	Model-specific block of settings
`0x000E`	FileLength	Long
`0x000F`	CustomFunctions	Model-specific custom function settings
`0x0010`	ModelID	Long that identifies the camera model
`0x0011`	MovieInfo	Movie settings
`0x0012`	AFInfo	Autofocus points
`0x0013`	ThumbnailImageValidArea	4 shorts; zeros for full frame
`0x0015`	SerialNumberFormat	`0x90000000` format 1, `0xA0000000` format 2
`0x001A`	SuperMacro	0 off, 1 or 2 on
`0x001C`	DateStampMode	0 off, 1 date, 2 date and time
`0x001D`	MyColors	Colour effect settings
`0x001E`	FirmwareRevision	Long
`0x0023`	Categories	2 longs of category flags
`0x0024`, `0x0025`, `0x002F`	FaceDetect1, 2, 3	Face detection results
`0x0026`, `0x003C`	AFInfo2, AFInfo3	Newer autofocus point data
`0x0027`	ContrastInfo	Contrast settings
`0x0028`	ImageUniqueID	16 bytes
`0x0029`	WBInfo	White balance information
`0x0031`	SmartAutoScene	Scene detection
`0x0035`	TimeInfo	Time zone and daylight saving
`0x0038`	BatteryType	Battery model
`0x0081`, `0x0082`	RawDataOffset, RawDataLength	Raw data position (older cameras)
`0x0083`	OriginalDecisionDataOffset	Offset of image verification data
`0x0090`–`0x0092`	CustomFunctions1D, PersonalFunctions, PersonalFunctionValues	EOS-1D series settings
`0x0093`	FileInfo	File number, bracketing, raw quality and more
`0x0094`	AFPointsInFocus1D	EOS-1D focus points
`0x0095`	LensModel	Text
`0x0096`	SerialInfo or InternalSerialNumber	Text
`0x0097`	DustRemovalData	Dust spot data
`0x0098`	CropInfo	Crop margins
`0x0099`	CustomFunctions2	Custom functions of newer cameras
`0x009A`	AspectInfo	Aspect ratio and cropped size
`0x00A0`	ProcessingInfo	Tone curve, sharpness, picture style, white balance, colour temperature
`0x00A1`–`0x00A4`	ToneCurveTable, SharpnessTable, SharpnessFreqTable, WhiteBalanceTable	Tables
`0x00A9`	ColorBalance	White balance levels (older cameras)
`0x00AA`	MeasuredColor	Measured RGGB levels
`0x00AE`	ColorTemperature	Short
`0x00B0`	Flags	Modified-file flags
`0x00B1`	ModifiedInfo	Settings changed after shooting
`0x00B2`, `0x00B3`	ToneCurveMatching, WhiteBalanceMatching	Tables
`0x00B4`	ColorSpace	1 sRGB, 2 Adobe RGB, 65535 not set
`0x00B6`	PreviewImageInfo	Size and position of the preview
`0x00D0`	VRDOffset	Offset of Canon editing recipe data, if any
`0x00E0`	SensorInfo	Sensor size and borders (below)
`0x4001`	ColorData	White balance levels, colour temperatures, black levels; one of about a dozen versions, told apart by the entry count
`0x4002`	CRWParam	Unknown
`0x4003`	ColorInfo	Saturation, colour tone, colour space
`0x4005`	Flavor	Unknown large block
`0x4008`, `0x4009`	PictureStyleUserDef, PictureStylePC	Base styles of user picture styles
`0x4010`	CustomPictureStyleFileName	Text
`0x4013`	AFMicroAdj	Autofocus micro-adjustment
`0x4015`, `0x4016`	VignettingCorr, VignettingCorr2	Peripheral illumination correction
`0x4018`	LightingOpt	Auto lighting optimiser, highlight priority, noise reduction
`0x4019`	LensInfo	Lens serial number
`0x4020`	AmbienceInfo	Ambience selection
`0x4021`	MultiExp	Multiple exposure settings
`0x4024`	FilterInfo	Creative filters
`0x4025`	HDRInfo	HDR mode settings
`0x4026`	LogInfo	Log recording settings
`0x4027`	FirmwareInfo	Firmware details
`0x4028`	AFConfig	Autofocus configuration
`0x402E`, `0x4033`, `0x4035`, `0x4045`	LensCorrectionData	Lens correction data, not decoded
`0x403F`	RawBurstModeRoll	Raw burst information (CR3)
`0x4053`	FocusBracketingInfo	Focus bracketing settings
`0x4059`	LevelInfo	Electronic level readings

SensorInfo

Tag 0x00E0 is an array of shorts, numbered from 0. A raw decoder crops the sensor data to the borders given here.

Index	Field
1	Sensor width, including borders
2	Sensor height
5	Left border of the visible area
6	Top border
7	Right border (inclusive)
8	Bottom border (inclusive)
9–12	Left, top, right and bottom of the black mask

.CR2 File Format – Maker note

Main tags

SensorInfo