pyexiv2-developers team mailing list archive

["Alex A. Naanou" <alex.nanou@xxxxxxxxx>]

Nikon cameras also embed similar info, but I have not dug into it yet.

At this point a low priority for me, but I could provide RAW and jpeg
files if someone wanted to play with this ;)

On Wed, Jan 4, 2012 at 12:17, Olivier Tilloy <olivier@xxxxxxxxxx> wrote:
> On 2011-12-31, Jason Bishop <jason.bishop@xxxxxxxxx> wrote:
>> Hello all, just joined (thanks Olivier) and wanted to share a little bit
>> of code with you in case you thought it useful.  I got a canon 7d little
>> while ago and noticed that the builtin screen indicates with red boxes
>> which focus points were used.  I thought that was interesting so I went
>> trudging through the exif info to see if I could generate images showing
>> the focus points as well.  this is what i ended up with.  grey boxes
>> showing all focus points. white for subset which were active when the
>> shot was composed, and red for the ones that were used to take the shot.
>>  please excuse the code duplication, i haven't cleaned up the code yet
>> to deal with dcraw rotating the image for me.  You can just ignore the
>> clauses for rotatepic==true.
>
> Very interesting, thanks for sharing Jason!
>
> Could you maybe post somewhere an original picture that embeds such
> information? I’m curious to see the visual result, but I don’t own a
> Canon camera.
>
> Also, do you know whether those magic values you use to extract the data
> are standard across all Canon cameras, or if they vary from one model to
> the other? Did you base your work on some sort of specification, or did
> you have to reverse-engineer the data?
>
>> I was thinking that perhaps these values (focuspointwidth,
>> focuspointheight, focuspointxpos, focuspointypos, activeafpoints,
>> afpoints) could be exposed more directly.  interested in your thoughts.
>
> It would make sense, especially if the format is common across all Canon
> cameras. I’m thinking that it may be a good candidate for an API such as
> the one requested in http://pad.lv/724185
>
> Cheers,
>
> Olivier
>
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-- 
Alex.