Thanks John, that seems reassuring, but I thought the GPS Timestamp was supposed to be UTC (or GMT as I call it)? Which is surely independent of DST and timezones? I assume it's also the timestamp you'd find in a GPX file downloaded from any GPS-enabled device, whether dedicated or inbuilt to a smartphone.

I'm wondering if perhaps different devices adjust the UTC value to get their 'GPS Timestamp' for the EXIF metadata? Presumably thinking that's more 'user friendly'? If so then IMO that defeats the purpose of a universal standard!

Do you have any examples in your files we can mull over please?

EDIT, more info:

Self explanatory screenshot showing an apparently correct result:

Hi Terry

. . . . I thought the GPS Timestamp was supposed to be UTC . . . . I'm wondering if perhaps different devices adjust the UTC value to get their 'GPS Timestamp' for the EXIF metadata? Presumably thinking that's more 'user friendly'? . . . .

It is, and I think you are correct - some devices eg mobiles, automatically adjust their time to 'local time', based on the local phone network zone, however others, eg my old sat nav, used the GPS time data and then adjusted its local time to GPS+ locale offset, however, I had to set the locale - for some reason it did not use the GPS location to calculate the offset.

I seem to remember we have had a similar discussion before on this topic because my video camera gives 2 different time stamps based the 'home' timezone or, if the GPS is on, the GPS date time + locale offset derived from the cameras location, however this can be 1 hour out as DST, AFAICS, is not programmed into it, - the camera has a world map built into so I can see where video and pictures were taken 'in camera'.

HTH

John EB

Hi John,

Thanks for the helpful follow up. I've come to the conclusion we cannot rely on 'GPS TimeStamp' (with logical manual adjustment) as a confirmation of (or alternative to) 'Date TimeOriginal' for determining a JPG's local time taken.

I also reckon that for three of our five days in Italy my iPhone's time zone setting must somehow have been wrong. Can't fathom it because I just let it do its stuff automatically. And I think I'd have noticed if the home screen time was an hour slow! Unfortunately I've finished my MEP video for two of those three days, so I'm going to have to redo them.😟

Thanks for the help and have a good weekend.

Hi Terry,

I admire your precision. I try to avoid this, as I have enough trouble trying to find enough time to do anything much. Sometimes I do things by day, but I found that even that is problematic. Overnight travel camping was a problem, as I took photos and video upon arrival and/or the next morning prior to departure. I took the easy way out and did a VdG travel route per day, then everything along the way and at the destination, whether or not it was filmed the next day. Then started with the VdG for the next leg. I ran into problems with time zone changes and the cameras being out of sync with one on daylight savings, the other on standard, and then forgetting to change the time zone on top of it. So I just try to make a story out of it.

I'm off to Africa again in another week. Too much work, not enough Magix.

Regards,

John CB

Hi John CB

. . . . So I just try to make a story out of it. . . . .

Same here - often gey 'that shot' the next day or just prior to leaving somewhere. Artisitc licence comes in to play telling the story rather than the actual sequence of events.

However I can understand Terry's methodology particularly when covering walks/hikes, which by their nature tend to be one way and give only one chance to get the shots.

. . . . I'm off to Africa again in another week. Too much work, not enough Magix. . . . .

Too true 🙁

John EB

Hi Terry

Had a thought after posting above - have you tried taking a photo of the data and time, eg written on a pad at the start of the day and used this as a relative reference for the remainder of the days photos?

IIRC you use one of the bulk renaming programs - and could you automatically fix the time issue by bulk adjustment using the actual time/date and the 'taken time' from the reference photo to working out the correct date/time for the remainder - hope that makes sense.

I have done this using one camera as a reference for the other (did not turn on GPS on my sportscam or time zone) with Advanced Renamer - using the delta option

John EB