digiKam database contains some metadata about photos...
It would be interesting to see summary information or statistics, such as focal length or other data from table ImageMetadata

For example, I use following script to see most used focal ranges (for new lenses selection):

#!/bin/sh

DK_CONF="${HOME}/.kde4/share/config/digikamrc"

eval `awk '/Database Name=/ {printf "DB%s/digikam4.db", $2}' ${DK_CONF}`

if [ $# -eq 1 ]
then
  QUERY="select count(m.imageid), m.focalLength from ImageMetadata m, Images i where i.id=m.imageid and i.album=${1} group by m.focalLength order by m.focalLength"
else
  QUERY="select id, relativePath from Albums order by id"
fi

sqlite3 ${DBName} "${QUERY}"

Reproducible: Always