On 11/28/2014 08:03 PM, Andre Bischof wrote:
Hi!
Probably you found a solution as of now, but as I stumbled
upon a very similar issue...
> I manage to apply the time shift (I'm from Germany,
> Cologne, which should be the same timezone as
> Europe/Berlin, and the pics were takin in Istanbul, which
> should be GMT+2), darktable gives me a message that it
> changed a certain amount of pics, and I see the changes in
> the exif afterwards.
So, as me, you left your camera set to your "home time
zone". Probably with correct setting of the DST. On a recent
trip I did the same, so my camera stayed at CET (but I
missed to correct for DST, so I had effetively +1 to take
into account.)
As you did I calculated time shift between the photo of my
gps device and it's EXIF timestamp, which gave me a nice
-7:00:50, the expected result of the pure zonal shift plus
the wrong DST and a slight shift in the cameras internal
clock ammounting for the 50 seconds.
I applied the changes. All is well, photos now show correct
time by means of DTs internal metadata. Then I applied my
GPX-track (merged from about 15 tracks taken druing my
trip), and, as you, got basically no image tagged. (A bunch
of them with entirely wrong coordinates.)
What I missed was basically this tiny select box in the
"Apply GPX Track" dialogue that says "Camera Time Zone".
Now, I found this guy is missleading. It doesn't want to
know which time zone your /camera/ is set to. What it DOES
want to know is which time zone your /metadata/ reflect. So
in my case the correct setting was NOT as I expected
"Europe/Berlin" (as set in camera), but it was "America/New
York" which was the time I corrected for. Of course my GPS
Unit showed the EST (as derived from it's position) when I
took the photo, and the -7:00:50 also reflected EST.
I understand this is the same for you: you'd need to tell
dt, that the camera time zone is Istambul. (Though you kept
your camera to CET, your corrected metadata are Istambul
Time...)
Probably, the "Camera time zone"-selector should be more
properly labled "Image time zone" or the like to make this
clearer?
One might also imagine that it should be a bit more
prominent, especially if the correction applied is > 1h it
is quite likely that you correct a time zone here. My camera
is not an atomic clock but its internal clock works
indeed pretty well...
Additionally, one misses this little guy. Point is IMHO, if
you're not working for National Geographic or the like
you're most likely in the same time zone most of the time so
you don't need to adjust it. So one just doesn't remember
it. And you never look for it at this location where you're
dealing with the GPX track. Probably a better location would
be in the module. (However it takes some space there and of
course you hardly ever change it-)
Finally, I wonder what a "proper" handling should look like.
Should I just set my camera to UTC to avoid all this time
zone shifts and this nasty DST thingy, and thus always
correct for UTC to get some consistency and also set the GPS
to use UTC only.
OTH as image metadata don't reflect the time zone set (this
is probably the initial bug, but out of the scope of anyone
to fix as it would require to fix EXIF...) is it better to
consistently set the camera? But then I need to remember
this and also to set it in DT. This definitely has more
sources of error. (None that can't be cured by math, of
course.)
--
Kind regards, / War is Peace.
| Freedom is Slavery.
Alexander Wagner | Ignorance is Strength.
|
| Theory : G. Orwell, "1984"
/ In practice: USA, since 2001
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