LR4, timezones and the mapping module

[dreed]

When using external GPS logs such as GPX files, there are three potential timezones:
* the timezone in which the photo was captured
* the timezone in which the GPS log was created
* the timezone in which the host of LR is active in

When all three are the same, no problem: LR can see the timezone information in the GPX file and it all works nicely.

If I now change the timezone for the host running LR, that's when problems begin.

So far as I can see, LR has no concept of which timezone a photo belongs to and perhaps it is this that is the cause of problems.

If I take a photo at 1pm in Paris, lad it into LR, take that laptop to London, then laptop's timezone changes but the photo was still taken at 1pm but now it was taken at 1pm London time in Paris and the GPX file that previously was perfectly aligned is no longer so.

Ok, I'm starting to confuse myself... to me, what appears to be the problem is that LR doesn't have a concept of which TZ an image belongs to and thus it cannot align it properly wit GPS logs, etc. Does that match the experience of others?

[Rhossydd]

I think this has been discussed before, and yes there are issues with it.

You'll probably need to work out a time zone offset to get the right locations.
I ensure that any time I expect to use a GPS location system I take one photo in the series at a known time and location. Maybe your watch or of the data logger when you record a waypoint. Then you have a reliable reference to check and calculate the offset from.

[Robert55]

Many camera's do not add a time-zone stamp to exif, which is where the trouble starts. I was using Geosetter [which uses exiftool] before Lr added maps and was not impressed enough by what Lr offers in this to change. What I do in Geosetter is add a timezone stamp, correct the time stamp if necessary, and add the location data from the gps track.
I realise this is an extra app / step, but it works.

[dreed]

Many camera's do not add a time-zone stamp to exif, which is where the trouble starts. I was using Geosetter [which uses exiftool] before Lr added maps and was not impressed enough by what Lr offers in this to change. What I do in Geosetter is add a timezone stamp, correct the time stamp if necessary, and add the location data from the gps track.
I realise this is an extra app / step, but it works.

Thanks for the tip on geosetter, I've downloaded it and it is working like a treat for me.

Do you go back and delete all of the "foo.bar_original" files that it creates after it writes out its own version of raw files with new EXIF metadata?

[Robert55]

I've never seen foo.bar original files. Are they big files? AFAIK it should not overwrite raw's, it just adds an xmp of about 10kb. I've seen it making xmp_original when I did not do things in the right order. Those could be safely deleted.

I'm on W7 64; raw's are Canon, Sony, Fuji

BTW: geosetter is in general a very nice GUI for editing exif in exiftool

[dreed]

If you go into "File" -> "Settings" and then choose the "File Options" panel, you get a list of file types.

If you click on (say) Canon (CR2, CRW) you have options such as:
[] Save data in XMP sidecar files
   [] Update existing data in images *
   [] Always update Exif data (GPS and taken date) in image *
[] Don't Create Internal XMP Data if it Doesn't Exist Already
[] Save IPTC Data as Unicode
[] If IPTC Data Exists alreay, Use It As Is
[] Overwrite Original File when Saving Changes *

* - this to me would imply that raw files can be updated

[AFairley]

When I used GeoSetter, I had it configured to overwrite raw files and it did.

[FabienP]

* the timezone in which the GPS log was created

I would assume that most GPS devices log time in UTC (Coordinated Universal Time). Lightroom was probably designed with that fact in mind so that the user would only have to indicate a time offset between the local time (as defined in the raw or jpeg file) and UTC.

Ignoring timezones in camera can be a good thing since this information will change over time and will not be updated in new firmware releases. My Sony RX100 and A7 cameras have different timezone definitions for some countries.

[Robert55]

Sony is different in that they have timezone as a settable option, including DST IIRC, but I think most other brands just write a time without any code or offset.