Date and Time Metadata in Photos

Date and Time Fields in EXIF

EXIF defines three distinct date/time fields, each serving a different purpose. Understanding the differences is critical for photo management, forensic analysis, and timeline reconstruction.

The Three Timestamps

DateTimeOriginal (Tag 0x9003) — The date and time when the original image data was generated. For a camera, this is the moment the shutter was released. This is the most important timestamp for photographers and the one used by most photo management software for sorting.

DateTimeDigitized (Tag 0x9004) — The date and time when the image was stored as digital data. For a direct digital capture, this is usually identical to DateTimeOriginal. For a scanned photograph, this would be the scan date while DateTimeOriginal would be the original shooting date (if known).

DateTime (Tag 0x0132) — The date and time the file was last modified. This changes whenever the image is edited and saved. It lives in IFD0 (the main image directory) rather than the EXIF sub-IFD.

Format

All three fields use the same format: YYYY:MM:DD HH:MM:SS in ASCII, exactly 20 bytes including the null terminator.

2024:07:15 14:30:45

Note the colon separators in the date portion — this is different from ISO 8601 which uses hyphens.

Subsecond Precision

For cameras that record subsecond timing (important for burst shooting), three additional tags provide fractional seconds:

• SubSecTime — Subseconds for DateTime
• SubSecTimeOriginal — Subseconds for DateTimeOriginal
• SubSecTimeDigitized — Subseconds for DateTimeDigitized

These are stored as ASCII strings like "123" meaning 0.123 seconds.

Timezone Handling

A significant limitation of EXIF is that the standard timestamps do not include timezone information. A photo timestamped "2024:07:15 14:30:45" could be in any timezone. Some cameras record timezone offset in the MakerNote (proprietary) section, and EXIF 2.31+ added OffsetTime tags:

• OffsetTime: Timezone offset for DateTime (e.g., "+09:00")
• OffsetTimeOriginal: Timezone for DateTimeOriginal
• OffsetTimeDigitized: Timezone for DateTimeDigitized

GPS Timestamps

The GPS IFD includes its own timestamp (GPSTimeStamp) which is always in UTC. Combined with GPSDateStamp, this provides an unambiguous time reference that can be used to determine the timezone of the other timestamps.