[Digikam-devel] [Bug 182013] sensitivity is not shown for rw2 files

[Matthias Welwarsky]

Sorry, b.k.o is offline, responding by email:

On Tuesday 27 January 2009 14:50:20 Andreas Huggel wrote:
> --- exiv2 -pp should also report the thumbnail image (with -ep you can
> extract it)
>
> There are two pairs of tags in the Panasonic images which look like size
> tags, but I'm not yet sure what exactly they mean:
>
> Exif.Image.0x0002 Short 1 3724
> Exif.Image.0x0003 Short 1 2754
>
> and
>
> Exif.Image.0x0006 Short 1 2742
> Exif.Image.0x0007 Short 1 3656
>
> The first two contain the same numbers as those shown by dcraw, maybe I
> should use these as the pixel size values.
>
> Any suggestions as to the meaning of these tags from the Panasonic camera
> owners? Can you confirm which pair corresponds to the actual image size?

0x0002 and 0x0003 according to exiftool are the sensor width and height, while 
0x0006 and 0x0007 are Image height and width. 0x0004 is sensor top border, 
0x0005 is sensor left border. 

Now, for my camera this is as follows:
Exif.Image.0x0002                            Short       1  4060        
Exif.Image.0x0003                            Short       1  3016        
Exif.Image.0x0004                            Short       1  4           
Exif.Image.0x0005                            Short       1  8           
Exif.Image.0x0006                            Short       1  3004        
Exif.Image.0x0007                            Short       1  4008        

I would have assumed that sensor height - 2* top border = image height, but as 
you can see the numbers don't add up. The out-of-camera JPEGs are 4000x3000, 
which corresponds to (image height - top border) x (image width - left 
border). I think now that the tags 0x4 to 0x7 are only hints for the 
processing software about how many usable pixels are there. The raw image is 
probably the size of the sensor, so I'm tempted to say 0x2 and 0x3 are the 
correct raw image size. its then up to the processor to chose a suitable 
portion of the sensor area.

regards,
matthias

>
> -ahu.