Version:           1.4.0 (using KDE 4.5.0) 
OS:                Linux

I had a problem with the AF. Currently there's a lot of discussion going on about bad shots due to not correct working AF, e.g. on Canon's 40D or even 7D, Most of them are sort of a PEBKAC problem, e.g. using multipoint AF not exactly knowing what this means for unimportant but closer objects.

So I wanted to know what focus point were actually used for my shots an was looking for a way to display them somehow on the computer.

My first idea was to write a small script using bash and ImageMagick to create an image with 19 layers each with a red square containing the AF sensor with that number, knowing the list of used sensors is in the EXIF data. But then I detected, that Canon even lists the positions of all AF sensors in (newer camera's?) EXIF data.

Using exiftool I found the following exntries using a Canon 7D.

AFAreaWidths                    : 222 222 222 222 222 222 222 222 222 222 222 222 222 222 222 222 222 222 222
AFAreaHeights                   : 266 266 266 266 266 266 266 266 266 266 266 266 266 266 266 266 266 266 266
AFAreaXPositions                : -1373 -881 -881 -881 -393 -393 -393 0 0 0 0 0 393 393 393 881 881 881 1373
AFAreaYPositions                : 0 393 0 -393 393 0 -393 743 393 0 -393 -743 393 0 -393 393 0 -393 0
AFPointsInFocus                 : 1,7,8
AFPointsSelected                : 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18

With that information it will be easy for me, and probably any digikam programmer, to generate a view of all used/unsused/avaiable AF sensors that can be turned on as an overly of the currently displayed image, either in the viewer or editor.

I will test that using transparent gimp layers this evening and double check the results using test images.


Reproducible: Didn't try