pyexiv2-developers team mailing list archive

[Jason Bishop <jason.bishop@xxxxxxxxx>]

A useful link (phil's again)
http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/Canon.html#AFInfo2

Also has description of the camera specific bits.  If the prevailing
attitude is to let the canon marketing geniuses stew in their own juices
then I can certainly appreciate that.

Jason

On Wed, Jan 4, 2012 at 12:17 AM, 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
>