[Digikam-users] How does digiKam do raw conversions for the slide shows ?

[Linuxguy123]

On Wed, 2009-12-23 at 19:03 +0100, Milan Knížek wrote:

> JPEG preview may not be the same as JPEG thumbnail in general meaning.
> 
> E.g. Canon EOS 5D MII stores a small resolution JPEG, full resolution
> JPEG and raw data in the CR2 files. The full resolution JPEG is kind of
> equal to the JPEG that camera produces (if raw is not used), but
> possibly with lower JPEG quality settings.
> 
> Use
> 
> $ exiv2 -pp image.cr2
> Preview 1: image/jpeg, 160x120 pixels, 11197 bytes
> Preview 2: image/jpeg, 5616x3744 pixels, 1127852 bytes
> 
> to find out and
> 
> $ exiv2 -ep1,2 image.cr2
> 
> to actually extract the first and the second preview JPEG at the same
> time. (This is not conversion from RAW!)

>From one of my images:

$ exiv2 IMG_1551.CR2
File name       : IMG_1551.CR2
File size       : 16094373 Bytes
MIME type       : image/x-canon-cr2
Image size      : 4272 x 2848
Camera make     : Canon
Camera model    : Canon EOS DIGITAL REBEL XSi
Image timestamp : 2009:12:19 02:40:35
Image number    :
Exposure time   : 1/60 s
Aperture        : F5.6
Exposure bias   : 0 EV
Flash           : Yes, compulsory
Flash bias      : 0 EV
Focal length    : 29.0 mm
Subject distance: 0
ISO speed       : 800
Exposure mode   : Manual
Metering mode   : Multi-segment
Macro mode      : Off
Image quality   : RAW
Exif Resolution : 2256 x 1504
White balance   : Auto
Thumbnail       : image/jpeg, 7397 Bytes
Copyright       :
Exif comment    :

$ exiv2 -pp IMG_1551.CR2
Preview 1: image/jpeg, 160x120 pixels, 7397
bytes                          
Preview 2: image/jpeg, 2256x1504 pixels, 651767 bytes  

So the raw image (4272 x 2848) would have even more resolution than the
large EXIF image (2256 x 1504) that was used on the slide show.