DateTimeOriginal: capture time, time zones, and EXIF dates

Tag definition and companion fields

DateTimeOriginal is 0x9003 in ExifIFD, conventionally stored as ASCII in YYYY:MM:DD HH:MM:SS form. SubSecTimeOriginal (0x9291) supplies fractional seconds, and OffsetTimeOriginal (0x9011) supplies the UTC offset.

Sources: ExifTool EXIF tag definitions

Worked example: reconstructing an instant

An illustrative capture time of 2026:08:15 14:30:00, a subsecond value of 125, and an offset of −04:00 combine to 2026-08-15T14:30:00.125-04:00. That is the same instant as 2026-08-15T18:30:00.125Z.

Without the offset, retain a local clock reading with an unknown time zone. Appending Z would assert UTC without evidence.

exiftool -G1 -a -s -DateTimeOriginal -SubSecTimeOriginal -OffsetTimeOriginal photo.jpg

Capture time versus file dates

File creation and modification dates describe the filesystem copy and can change during transfer. They need not match the capture time. Digitization time and capture time may also differ, especially for scans.

XMP represents dates differently from the base EXIF string. Two fields labeled DateTimeOriginal can therefore have different formatting and detail. Compare groups and companion tags before deciding that one value is wrong.

Sources: Adobe XMP EXIF namespace

Parsing and evidentiary limits

Parse the EXIF components explicitly instead of passing the colon-separated date to a browser’s generic Date parser. Preserve the source string, validate calendar ranges, and distinguish missing values from parse errors.

A correctly formatted date may still be inaccurate because the camera clock was wrong. For an investigation, compare independent time evidence and document any correction. Do not silently rewrite the source file.