Add computed_copyright, exif_lens, exif_lensid as selectable metadata

Actually some formats store more than this:

 $ exiflist XXXX0985.CR2
 Focal Length (mm) : 400.00
 Focal Length Long : 400
 Focal Length Short : 100

...and there's more, e.g.:

 File name: XXXX0985.CR2
 Camera Model Name: Canon EOS-1Ds Mark II
 Firmware: Firmware Version 1.1.4
 Shooting Date/Time: 6/9/2007 07:56:17
 Tv(Shutter Speed): 1/80Sec.
 Av(Aperture Value): F11
 Metering Modes: Evaluative metering
 Exposure Compensation: +1/3
 ISO Speed: 100
 Lens: 70-200mm
 Focal Length: 169.0 mm
 Image size: 4992 x 3328
 Image Quality: RAW
 Flash: Off
 White Balance: Color temperature
 AF mode: One-Shot AF
 Picture Style: -
 Parameters: Tone Curve : Standard: Sharpness level : -: Pattern Sharpness : -: Contrast : 0: Sharpness : 0: Color saturation : 0: Color tone : 0: Long exposure noise reduction : -: High ISO speed noise reduction : -: Highlight tone priority : -
 Color matrix: 1
 Color Space: sRGB
 File Size: 24000 KB
 Dust Delete Data: No
 Drive Mode: Single-frame shooting
 GPS Data: Satellite signal status : -: Date(UTC) : -: Latitude : -: Longitude : -: Altitude : -: Geographic coordinate system : -
 Owner's Name: -
 Camera Body No.: XXXXXX

... or

$ exiftags DSC09842.JPG
exiftags: maker note not supported
Camera-Specific Properties:

Equipment Make: SONY
Camera Model: DSLR-A900
Camera Software: DSLR-A900 v2.00
Maximum Lens Aperture: f/4.0
Focal Length (35mm Equiv): 35 mm

Image-Specific Properties:

Image Orientation: Top, Left-Hand
Horizontal Resolution: 350 dpi
Vertical Resolution: 350 dpi
Image Created: 2011:09:27 14:12:28
Exposure Time: 1/100 sec
F-Number: f/10.0
Exposure Program: Normal Program
ISO Speed Rating: 200
Brightness: 7.5 EV
Exposure Bias: 0 EV
Metering Mode: Center Weighted Average
Light Source: Unknown
Flash: No Flash, Compulsory
Focal Length: 35.00 mm
Color Space Information: sRGB
Image Width: 6048
Image Height: 4032
Rendering: Normal
Exposure Mode: Auto
White Balance: Auto
Scene Capture Type: Standard
Contrast: Normal
Saturation: Normal
Sharpness: Normal

As the tool exifprobe shows, it is a bit more complicated than the parsed listings above might suggest (see attachment); isn't there a more generic way to access the data actually stored? Helper tools like exiftool seem to do the heavy lifting (parsing data structures, independent from maker specific programs), and appear to extract a lot more data from image files than currently is possible. E.g., a file dumped with exifprobe (like in the attachement) maps to a clean output like this:

ExifTool Version Number         : 8.15
File Name                       : DSC09833.JPG
Directory                       : .
File Size                       : 28 MB
File Modification Date/Time     : 2011:09:27 11:47:22+02:00
File Permissions                : rw-r--r--
File Type                       : JPEG
MIME Type                       : image/jpeg
Exif Byte Order                 : Little-endian (Intel, II)
Image Description               : SONY DSC
Make                            : SONY
Camera Model Name               : DSLR-A900
Orientation                     : Horizontal (normal)
X Resolution                    : 350
Y Resolution                    : 350
Resolution Unit                 : inches
Software                        : DSLR-A900 v2.00
Modify Date                     : 2011:09:27 11:47:21
Y Cb Cr Positioning             : Co-sited
Exposure Time                   : 1/250
F Number                        : 9.0
Exposure Program                : Program AE
ISO                             : 200
Exif Version                    : 0221
Date/Time Original              : 2011:09:27 11:47:21
Create Date                     : 2011:09:27 11:47:21
Components Configuration        : Y, Cb, Cr, -
Compressed Bits Per Pixel       : 8
Brightness Value                : 8.37
Exposure Compensation           : 0
Max Aperture Value              : 3.2
Light Source                    : Unknown
Flash                           : Off, Did not fire
Focal Length                    : 24.0 mm
Flash Exposure Compensation     : 0
Teleconverter                   : None
White Balance Fine Tune         : 0
Focus Mode                      : AF-S
AF Area Mode                    : Wide
Local AF Area Point             : Right
Metering Mode                   : Center-weighted Average
ISO Setting                     : Auto
Dynamic Range Optimizer Mode    : Standard
Dynamic Range Optimizer Level   : 4
Creative Style                  : Standard
Zone Matching Value             : 0
Brightness                      : 0
Flash Mode                      : ADI
Rotation                        : Horizontal (normal)
Sony Image Size                 : Large
Aspect Ratio                    : 3:2
Quality                         : Extra Fine
Exposure Level Increments       : 1/3 EV
White Balance                   : Auto
Preview Image                   : (Binary data 1337538 bytes, use -b option to extract)
Color Temperature               : Auto
Color Compensation Filter       : 0
Scene Mode                      : Standard
Zone Matching                   : ISO Setting Used
Dynamic Range Optimizer         : Standard
Image Stabilization             : On
Lens Type                       : Minolta AF 17-35mm F2.8-4 (D)
Color Mode                      : Standard
User Comment                    : 
Flashpix Version                : 0100
Color Space                     : sRGB
Exif Image Width                : 6048
Exif Image Height               : 4032
Interoperability Index          : R98 - DCF basic file (sRGB)
Interoperability Version        : 0100
File Source                     : Digital Camera
Scene Type                      : Directly photographed
Custom Rendered                 : Normal
Exposure Mode                   : Auto
Focal Length In 35mm Format     : 24 mm
Scene Capture Type              : Standard
Contrast                        : Normal
Saturation                      : Normal
Sharpness                       : Normal
Compression                     : JPEG (old-style)
Thumbnail Offset                : 40306
Thumbnail Length                : 8846
Image Width                     : 6048
Image Height                    : 4032
Encoding Process                : Baseline DCT, Huffman coding
Bits Per Sample                 : 8
Color Components                : 3
Y Cb Cr Sub Sampling            : YCbCr4:2:2 (2 1)
Aperture                        : 9.0
Image Size                      : 6048x4032
Lens ID                         : Minolta AF 17-35mm F2.8-4 (D)
Scale Factor To 35 mm Equivalent: 1.0
Shutter Speed                   : 1/250
Thumbnail Image                 : (Binary data 8846 bytes, use -b option to extract)
Circle Of Confusion             : 0.030 mm
Field Of View                   : 73.7 deg
Focal Length                    : 24.0 mm (35 mm equivalent: 24.0 mm)
Hyperfocal Distance             : 2.13 m
Light Value                     : 13.3

An external dependency - like on exiftool - wouldn't hurt as the program is free software (license), and it is available for *nix, Windows, and Mac OS X. At least to me it seems that the benefits would significanty overweight the drawbacks...

Any update for this?
I still can't select the exif lens data...

Thanks!

I noticed "focal length in 35mm" is missing in 7.x-1.2 selecting options.
Any update? Thanks!

Hi,
Besides lens(id) I also found copyright missing. Even after replacing sample.jpg with an image that DOES contain this value. So I added this (computed_copyright) and re-rolled patch from #5 so that it applies cleanly.

So this patch adds:

• computed_copyright
• exif_lens
• exif_lensid

@hohl not really related to this issue, but are you sure your source image has this exif field?

Please test and/or commit.

Patch from #6 still applies cleanly on a current dev version (30 september). Please somebody test and review.

integrated in branch 7.x