Finder time-travels to the future

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Have never had pictures taken in the future, but a subset of my image files showed tomorrow’s time stamp, next to the ones I took roughly at the same time today.

It seems this is because I forgot to change the time settings in my camera from a time zone that is ahead of us. Ooops.

Many Photo editing tools allow you to change play with the EXIF time and date fields and propagate the changes to file creation and modification dates. For example, I’ve linked to a screen capture showing the menu for Graphic Converter, where the change I choose would affect the selected photos.

That’s amazing. You gotta love that Apple engineers are this detailed.

This happens to me all the time (no pun intended) when I fly from Asia to the U.S. I get lots of files written or saved “Tomorrow” during the first part of my first day there, especially if I worked on the airplane.

Enjoy it. It’s completely accurate, isn’t it.

Interesting. That would seem to indicate that the timestamps stored are in local time, not UTC. So you save a file, whose timestamp is stored in local time, then cross the International Date Line from west-to-east (causing you to lose a day), the computer would see those dates in the future.

If the system was storing timestamps using UTC, then this could never happen. When your local comptuer’s time-zone changes, the times presented in the Finder would change accordingly, to reflect the timestamp in the (new) local time.

According to what I’ve been able to find in web searches, the old HFS is supposed to use local time, while HFS+ and APFS are supposed to use UTC.

If you were saving files to a FAT-formatted volume (e.g. a USB stick or SD card intended to be portable to Windows systems), then the timestamps are probably going to be saved in local time.

Timestamps seen in the Finder appear to be stored in UTC (or local with the UTC offset). I tested this by temporarily using the Date and Time system preference to shift my location. I then saw all the Date Modified timestamps in a Finder window change.

When it comes to photos, though, I don’t believe that the standard photo metadata Information (EXIF) included any Time Zone provision. So, when photos were transferred from a camera to a computer, they use the EXIF time and date as the creation date. As I previously noted, photo editors usually include some provision for batch adjusting date and time to account for this.

By the way, there is an interesting current bug in the Photos app related to this (previously noted by me). Currently, I take almost all my photos on my iPhone and use iCloud Photos for storage. When I display a photo in IOS, it shows the date and time of the photo in local time where the photo was taken. However, on a Mac, it shows the local date and time for where it is being viewed. For example, I was in London earlier this year and took some outdoor photos at about 10:30am that are obviously daylight photos. When viewed on my Mac, however, they show up as taken at 2:30am (I’m in the Pacific Time Zone in California). When exported, the EXIF field uses the 2:30am time as the timestamp.

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If stored in UTC but displayed in local that would explain the behavior.

But it should also have a time zone offset and daylight savings time indicator stored. Note that the same file does correctly show the local time associated with the picture on mobile OS’s.

If there is anyone who is running the iOS or iPad OS beta and the macOS beta and using iCloud Photos, can you see if this is fixed in the new releases? I won’t waste time filing Feedback if it is.

The Mac OS is based on Unix, which stores date-times as seconds since midnight, January 1, 1970, GMT, which is an absolute time, not affected by timezone, so the time zone is not and need not be recorded with the timestamp. The displayed time is computed based on the users time zone setting. So, for this to occur, someone is not playing by the rules, probably the interface between the photo metadata and transferring to the Mac. If the photo was taken with an iPhone, then shame on Apple.

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I think people are confusing OS file date formats with the photography EXIF dates. A typical EXIF date looks like:

2003:08:11 16:45:32

and should be the camera local clock time. Older versions of EXIF don’t have a standard way to include the time zone, though it’s possible that a manufacturer’s proprietary field could have it. Since mid 2016 version 2.31 (via wikipedia), there are tags to store the time zone: “OffsetTime”, “OffsetTimeOriginal” and “OffsetTimeDigitized” which will generally be the current time-zone offset from UTC (e.g., -7:00 for PDT) for all of them.

Not all cameras/camera OS versions newer than mid 2016 are using the latest EXIF version. Checking through some photos, it looks like Apple upgraded EXIF from 2.21 to 2.31 in iOS 13, so they were years late to the party.

Know your camera and camera settings, and when in doubt about an anomaly and you want to see every bit of metadata for an image or video (many kinds of formats, and more metadata than just EXIF), use exiftool from Phil Harvey. It’s a free command line tool. There are graphical interfaces to view and edit much of it and a lot of photo software such as Graphic Converter uses exiftool under the hood, but I haven’t seen any third party interface show absolutely everything, let alone let you manipulate it, especially in the amazingly rich ways the tool allows. Photos.app shows almost nothing, but the dates it shows should be EXIF dates, not file dates which are usually but not always the same (within a second or so).

https://exiftool.org/

It’s an extremely powerful utility, but for a simple list of all metadata, once you install it, all you have to do is type (in Terminal):

exiftool filepath/filename

If you drag the file to the Terminal window after typing "exiftool ", you don’t have to type the path or filename, and you don’t have to worry about any special characters in the path or name.

More specifically, the Unix APIs all use GMT-based timestamps. The format for the timestamp actually stored on a storage device depends on what file system it is formatted with.

HFS+ and APFS (as far as I can figure out) are GMT based. The epoch date is 1/1/1904 for HFS+, and 1/1/1970 for APFS. (The older, deprecated, HFS format uses local time with a 1/1/1904 epoch).

The FAT file system uses local time with a 1/1/1980 epoch.

So, if you’ve got a FAT-formatted memory card from a camera, it should be using a local timestamp for the file time. This should be converted to GMT based on the computer’s timezone at the time of import, unless Photos chooses to use the EXIF data as the file’s timestamp.

Even so, this should not produce a future time unless someone is violating the rules. Like a computer or camera treating timestamps on a FAT volume as GMT when they shouldn’t be.

Most digital images include EXIF which stands for “Exchangeable image file format” and includes, amongst many details related to the image (such as camera type, focal length, aperture etc.), the timestamp at which the picture was taken.
The timestamp is derived from the system-time of the device that was used to take that picture.
Not all devices are synchronized to an atomic clock (or even to your computer, which may be deriving its clock from one such atomic clock). Some devices’ clock is configured manually by the user through menus, and some humans either don’t care adjusting the time or the date with precision. A day, or a year, or a decade off is not uncommon.

In short - if the camera is configured to a time in the future, the pictures it produces will appear as if they were taken (or rather will be taken???) in the future.
This has nothing to do with apple or finder…