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Timezone and Travel

Discussion in 'Open Discussion' started by agnieszka, Feb 17, 2016.

  1. agnieszka

    agnieszka Mu-43 Regular

    71
    May 1, 2015
    Central Coast, NSW Australia
    Agnieszka
    Hello,

    Just fielding a question on best-practice or how people manage date/time information on their photo metadata when travelling - especially when importing into Lightroom.

    on one hand, changing the camera's date/time for each location that warrants it could be problematic if one forgets to do it each time - rendering the wrong time on each subsequent photo and then who knows what time location was set. on the other, it would remove the need to do it after-capture.

    in terms of after-capture, Lightroom doesn't seem to be able to time-shift on import (is this accurate? i've only been using LR a short time) - which could be problematic with my import preset to copy files into dated folders (that is, a photo captured in canada at Monday 08:00 local time might be Sunday 22:00 in Australia (and therefore in camera if unchanged when travelling)). So the file would be added to a folder dated the day before, and one day of photos split into two separate day folders. i could time-shift after import but then i would also have to manually move the photos in LR from folder to folder where applicable. i could also import photos day-by-day and get the import preset to add a static date, but i expect i would lose the time stamp - and that's a lot of individual importing for, say, a 5 week trip.

    so, the other option is to copy images to the harddisk first, use something like exiftool to shift all image capture times for each location that requires it, and THEN import into Lightroom. but that just sounds like a lot of work and possibilty of things going wrong.

    so i'm wondering how others manage this problem? looking for the least-effort fastest-time solution but am aware that might not exist!
     
  2. PacNWMike

    PacNWMike Mu-43 Hall of Famer

    Dec 5, 2014
    Salish Sea
    guess?
    Set at home and forget it. Easier to calculate an individual photo in the unlikely event anyone cares rather than make a mess with divergent zones.
     
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  3. agnieszka

    agnieszka Mu-43 Regular

    71
    May 1, 2015
    Central Coast, NSW Australia
    Agnieszka
    LOL, 10 points for quickest and easiest method! I do sometimes need nudging to dial my OCD down from 11 to, say, a 5 or 6.

    Sent from my GT-I9505 using Tapatalk
     
  4. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    I never mess with time stamps even though GX7 and GX8 both have the option of a second time zone to stamp. Before we leave on a trip, I synchronize the (home time zone) clocks on my two bodies and my wife's camera so that LR gets them filed and displayed in approximately the right sequence.

    That's it. Too much risk of screwup in messing with time stamps compared to minuscule or zero benefit. Just IMHO.
     
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  5. budeny

    budeny Mu-43 All-Pro

    Mar 4, 2014
    Boulder, CO
    FYI, Olympus mobile app will sync time on camera when it connects to it via Wi-Fi.
    Can be an easy way to set time or mess up your timestamps.
     
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  6. Drdul

    Drdul Mu-43 Regular

    104
    May 16, 2015
    Vancouver, BC
    Richard
    I use a GPS logger app on my iPhone to geotag my photos in LR, so I need to change the camera time to local time. My helpful tip is that I set reminders on my phone in advance to remind me to change the time back (or to another time zone).
     
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  7. agnieszka

    agnieszka Mu-43 Regular

    71
    May 1, 2015
    Central Coast, NSW Australia
    Agnieszka
    That's a good point - i have started using a GPS logger too (though a stand-alone one). Haven't used it in any other timezone as yet.
     
  8. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Regarding getting a time stamp from your phone, that requires that you have phone service at your location. Traveling internationally that is rarely the case for me. When I do buy a local SIM card, I install it in an old GSM phone (Nexus One), not my regular phone.

    Re GPS, here is more than you wanted to know:

    (Backstory; I have developed software for aerial photography, Search & Rescue, that merges GPS track files from loggers into photographs' EXIF data blocks. I would not characterize the situation as a can of worms as it is well organized, but it is complex.)

    OK, start with this: All GPS receivers I am aware of use pieces of the NMEA 0183 data transmission specification. This is a semi-monster designed for a shared data bus on ships, accommodating transfer position data (GPS), automatic pilot control data, and a bunch of other stuff. For this M43 discussion you need to know that the GPS time stamp is always Zulu time.

    Now the photograph EXIF (Exchangeable image file format - Wikipedia, the free encyclopedia) block: There are two EXIF fields that are germane: DateTime is where the photo time stamp we're talking about here is stored. It is initially written when the photo is taken. The spec is silent on time zones, but obviously the convention is that the time stamp is based on the camera's setting -- whatever that might be. Actually, one might argue that it makes sense to set the camera to Zulu time; then you can easily translate to whatever time zone interests you.

    The second EXIF field of interest is GPSTimeStamp -- which is just what it sounds like. This one is always Zulu time. There is nothing in the specification, though, that addresses coordination of DateTime and GPSTimeStamp. To the spec, they are totally independent.

    If the camera has an internal GPS (or a tethered GPS) that can see the sky, life can be pretty good. The GPS information (over 30 EXIF fields in total) is filled in when the photo is snapped.

    If the GPS data is being logged separately and later merged into the photos, things get a little messier. Guaranteed that the camera time will not match GPS time to the millisecond, even if the time zone issues are worked out. Once that wrinkle is dealt with by calculating an offset, software can take the GPS data stream and use it to do whatever violence it cares to do in the EXIF.

    OK, with me so far? Here is the punch line: The GPS data is no help in determining the local time zone where the photo was shot. You can also not be sure that the photo time stamp will be updated by the logger interface software. My guess is that probably it will not. If the photo time stamp is to be updated to local time, the Zulu offset time of the local time zone (e.g., GMT+2) must have been provided by the user. So if you stay in one time zone when traveling (like India) there's a good chance that you can get it right. (If you remember.) If you are moving through time zones (like shooting out the window on a transoceanic flight) the chances are not so good.

    So my bottom line is the same: Set the camera to my home time zone, synchronize times on all cameras on the trip, and go take pictures!

    HTH
     
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  9. tkbslc

    tkbslc Mu-43 Hall of Famer

    What's the benefit? The time is the time, regardless. If I am in Rome and the clock says 5:11 PM, but my photos are stamped 9:11 AM MST - those are the same time! 9:11 MST is 5:11 CET in Rome.
     
  10. alan1972

    alan1972 Mu-43 Top Veteran

    592
    Jun 23, 2012
    Malaga, Spain
    Alan Grant
    Yes, this caught me out once before I knew about it. I connected to OI Share half way through a day of shooting, having changed time zone in the morning and not reset my camera. The later photos ended up with an earlier timestamp than the first part of the set, which puzzled me greatly viewing them in Lightroom some days later.

    It is actually a potentially useful feature, but I feel the app should warn you that it is tinkering with your camera settings, or even better give you the option to accept the change or not.
     
  11. PakkyT

    PakkyT Mu-43 Top Veteran

    765
    Jun 20, 2015
    New England
    It used to. I believe you either had to manually pick the function from menu to sync the time and/or the app would ask you if you wanted to. Later Oly changed it so whenever you connect to a camera, the camera's time is updated automatically and silently.

    I too got caught by this on a trip. Once I figured out what happened while on the trip after the first time zone change, to be consistent I made sure whenever we changed time zones, to connect the camera to the OI.Share app and then I would take a photo of my wrist watch. Once I got home, except for that first time change where I had to figure out where in my photos it happened, the rest of the trip I simply could select bunches of photos between "wristwatch" shots to Geotag them from my external stand alone GPS data logger's files.

    To the discussion about Geotagging, I too (with the exception of the OI.Share time change issue mentioned above) leave my camera's time set to my local (home) time. Then even when you cross time zones all my photos are GMT-5 and as oldracer points out my GPS data logs are all in GMT (Zulu). So I can pick ALL my photos I took on a trip, tell my computer program to match them to the data logs and geotag them and that all my photos are GMT-5. Then sit back and wait while it churns through them all. If you change time zones on your camera (or OI.Share does it to you like it did to me on that one trip), then you usually have to Geotag against GPS logs in chunks where this batch is GMT-5, then next set are GMT-6, then next -7, etc.
     
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  12. Drdul

    Drdul Mu-43 Regular

    104
    May 16, 2015
    Vancouver, BC
    Richard
    Interesting information about how GPS works. It would be much easier if we were all on the same UTC (what old racer called Zulu) time. So here's a question; What if I set my camera to UTC time and just left it like that? Then I'd never have to worry about moving from one time zone to another.

    I'm in Vancouver, which is 8 hours behind UTC. If I use the GPS Tracks app on my iPhone to generate a GPX file, and I then load that file in Lightroom and use it to geotag photos I took at the same time, will Lightroom assume the time on the photos is UTC or Pacific Standard Time? Is there a way to force Lightroom to geotag them correctly if the camera is set to UTC time?
     
  13. alan1972

    alan1972 Mu-43 Top Veteran

    592
    Jun 23, 2012
    Malaga, Spain
    Alan Grant
    I am not certain about the basic Lightroom functionality, but I know that Jeffrey Friedl's Geoencoding support plugin can handle this easily. I do all my location-related stuff in Lightroom through this plugin, I found it more flexible and clearer than Lightroom's own tools.
     
  14. Drdul

    Drdul Mu-43 Regular

    104
    May 16, 2015
    Vancouver, BC
    Richard
    Good to know. I use Jeffrey's Geoencoding plugin for other purposes (like adding sublocations), but haven't use it for geotagging from a GPX track because Adobe added that functionality to Lightroom. I'll give it a whirl and report back.
     
  15. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    Yes. I mentioned that in my post. Working with Zulu time can get a little confusing, though, if you are not doing it on a regular basis. For example, if you are shooting today 2/18/2016 in UTC-8 Vancouver at around 4PM, the photos you shoot before 4PM will be date stamped 2/18/2016 and the ones after 4PM will be stamped 2/19/2016 because at 4PM local time, UTC rolled through midnight. If you head that direction, I suggest you think in terms of military time; 4PM is 1600, add 8 to get 0000 and you realize it is midnight Zulu.

    Interesting! I have never looked at LR's geotagging stuff as I have never had any interest in geotagging my own photos. From poking around the various web demos, though, I see that it is necessary for you to specify the time offset between the GPX time and the camera times. So that is consistent with the point I made above. If you set the camera to UTC, then the offset is zero. If Vancouver local time, the offset is -8.

    If you don't get the offset to be correct, LR probably will complain and tell you that it can't match up the photos. There are some ways that software can try to guess what the offset is, but the user has to confirm the guess. For example, if you take photos for ten minutes during the hour from 3PM to 4PM and then give LR a GPX file that runs from 3PM to 5PM but with UTC-8 times, LR has no way of knowing whether you are UTC-8 or UTC-7.

    But back to our regularly scheduled program, in the tutorials I saw there was no indication that LR was stuffing data into the GPSTimeStamp field (but maye it is) and no indication that LR was altering DateTime based on the GPS data. This can actually get kind of messy, particularly if the GPX sample rate is slow relative to the speed the camera is moving across the ground and the speed at which photos are being shot. If you have five shots that are, in time, closest to one GPX sample then they will all get geotagged with that lat/long even though the shots may have been made many feet apart. But if LR also altered the DateTime then all five would all be tagged with the same DateTime value -- clearly an error.

    So .. this stuff can get complex. In my case I was working with photos shot from airplanes moving at a couple of hundred feet per second, so small time offset errors made things fairly messy. Basically, I had to use position sample rates in the neighborhood of 1/second and then interpolate both coordinates and times before adding the info to the EXIF. Even saying that oversimplifies a bit.
     
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  16. HarryS

    HarryS Mu-43 Top Veteran

    919
    Jun 23, 2012
    Midwest, USA
  17. Drdul

    Drdul Mu-43 Regular

    104
    May 16, 2015
    Vancouver, BC
    Richard
    Thanks for all the info, @oldracer@oldracer . I tested it this afternoon by setting the time on my camera to UTC and running the GPS Tracks app on my iPhone to generate a GPX tracklog. The photos came in showing the UTC time, which is 8 hours later than Vancouver time, as I guess there's no information embedded into the photo indicating the time zone. When I imported the tracklog into Lightroom, it displayed the times in local Vancouver time (when I open the tracklog in text editor, I see the times in UTC format, but Lightroom obviously knows that the track was recorded in Vancouver, and adjusts the times by 8 hours).

    So I had a difference of 8 hours between the photos and the tracklog. Fortunately, that was easy to deal with. After I selected the photos in the Map module, I chose the "Offset Time Zone" option, which shows the first and last times of the selected photos and the start and end times of the tracklog. The numbers are shown in red to indicate a mismatch. There's a slider below that, and all I had to do was drag it until the times matched (within an hour) and the numbers turned from red to black. The resulting offset was the correct 8 hours.

    Unfortunately, when using the time zone offset feature Lightroom adjusts the tracklog times, not the photo times, so after geotagging the photos I then had to go back to the Library module and select Metadata > Edit Capture Time... to shift the times on the photos back 8 hours. I suppose I could have adjusted the capture times by 8 hours before geotagging the photos, but it would have been nice if Lightroom would have adjusted the photo times when matching them to the tracklog times, instead of the other way around.

    Lightroom is my primary tool for geotagging, and because of the way it works the solution for me is to continue to set my camera time to the local time zone. If I am travelling through multiple time zones I will start and stop my tracklogs at time zone boundaries if possible, and change camera times then, too, but that only makes sense when moving between time zones every few days. If I was on an airplane shooting out the window, I would just set the camera time to UTC and deal with it later in Lightroom, or better yet, another geotagging application.
     
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  18. oldracer

    oldracer Mu-43 All-Pro

    Oct 1, 2010
    USA
    No problem. I'm glad it helped.

    All of this adjusting and tagging is very do-able if you thoroughly understand it. Making these "Update All" changes is always a little like juggling with hand grenades IMO, so I personally try to do as little of it as possible. But you obviously have the appetite, so have fun!

    Actually I think you could run into situations where this would be not nice at all. I think the LR data doctors were wise to not mess with DateTime using GPS data. Like the Hippocratic Oath says: "First, do no harm."
     
  19. agnieszka

    agnieszka Mu-43 Regular

    71
    May 1, 2015
    Central Coast, NSW Australia
    Agnieszka
    My geotagging workflow includes:
    Gps babel (to download tracks from my logger)
    Gps prune (to split and simplify/edit tracks)
    Geosetter (to apply the gps data to photos - works on raw and regular types) geosetter also adjusts date/time so gpx matches to photos - from memory it adjusts the photo capture time, not the gpx but it can shift even by a few seconds if you want (particularly handy if you're bushwalking/animal watching) and does batch (uses phil harveys exiftool to do the heavy lifting).

    Geosetter: Description

    I recently opened the maps module in LR and photos that I'd tagged using geosetter showed up in the module, so quite happy about that. :)

    As i mentioned earlier, I've yet to be in a different timezone with the gps logger to test how it fares with a time differential with the camera. I had not explored the shift feature of the maps module in lightroom - it's great to know it's there. Though i think i would prefer to keep my local time on camera and shift post-production.

    Sent from my GT-I9505 using Tapatalk
     
    Last edited: Feb 19, 2016
  20. alan1972

    alan1972 Mu-43 Top Veteran

    592
    Jun 23, 2012
    Malaga, Spain
    Alan Grant
    I think it just seems that way because Lightroom makes an initial assumption that you recorded the track in the same time zone as your computer. That assumption was correct in this example but might not be if you were travelling, where there are potentially three time zones to consider - UTC (the tracklog), local time where you took the photos, and local time where you are editing the photos (which strictly speaking should not be relevant). This is one of the things I found clearer with the JF plugin - you can get to the same result with the built in geotagging, but I found that the way JF presents it I was more confident that I had the settings right. I shuttle between Central and Western European time quite often for work reasons, so this matters to me!

    Another nice thing about the JF plugin is that you can load multiple tracklogs files at the same time - I have used this to tag photos from a multi-day trip, with a different tracklog for each day, in one go (without having to combine the tracklogs in any way outside Lightroom).
     
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