EXIF is a block of metadata a camera or phone embeds directly inside an image file at the moment it's captured — exposure settings, the date and time, the image's orientation, and often GPS coordinates if location services were on. It travels inside the same file as the picture, which is what separates it from metadata added later by a person or an app.
What's actually in it
The exact fields vary by device, but the categories that show up consistently are:
- Capture settings — aperture, shutter speed, ISO and similar exposure data, written by the camera at the moment of capture.
- Date and time — when the shutter was released, not when the file was later copied, edited or re-saved.
- Orientation — which way up the sensor was held, so a viewer can rotate the image correctly without anyone doing it by hand.
- GPS coordinates — present only if location services were enabled on the device, and often the first field people strip out before sharing a photo publicly.
EXIF versus the metadata added afterward
EXIF is written once, by the device, at capture. Keywords, captions, ratings and edit history — the kind of metadata a person or an app adds while organising a library — live in a different set of standards entirely, most commonly IPTC and XMP, and they can be added, changed or stripped at any point after the file exists. A reference manager that reads EXIF, IPTC and XMP, as the full comparison against refern covers in detail, is reading two different kinds of history: what the camera recorded, and what somebody said about the picture afterward.
What Coii Ref reads
Coii Ref reads EXIF that's already embedded in a file — dimensions, capture data, colour — into its search index, so a query can filter on what the camera recorded without anyone typing a tag first. It doesn't write new EXIF into a file or attach IPTC or XMP alongside it; ratings, tags and notes made inside Coii Ref live in its own workspace database rather than back in the image. The comparison linked above covers where that narrower approach costs something against a tool that reads and writes a wider set of embedded standards.
Why it matters for search
EXIF turns "find the photos from that shoot in March" into a query that doesn't depend on anyone having tagged anything, because the date and the camera settings were already there the moment the file was created. What a reference manager actually does with metadata like this is the wider version of the same idea.
Why EXIF alone isn't enough to organise by
Capture data answers "when and how was this taken," not "why did I keep it" or "what is this a reference for." Two photographs shot on the same camera with identical settings can belong in completely different parts of a library — one a lighting study, the other kept for a colour palette — and EXIF has no field for either of those judgments, because it was never meant to record them. That's the gap tags, ratings and notes exist to fill: the part of a file's description that only a person looking at the image can actually supply, sitting alongside metadata the camera wrote in automatically the moment the shutter closed.