What EXIF data is
EXIF (Exchangeable image file format) is a standard for information stored inside image files. Cameras and phones write it when a photo is taken: which device, which settings, when and, if location is switched on, where. The standard is called CIPA DC-008 (originally from JEITA). It describes named values (tags) that are kept in directories (IFDs): IFD0 holds the basic data of the image and the camera, the Exif directory the shooting data, the GPS directory the location, and a second directory (IFD1) can hold a small preview image.
What a photo can reveal
A photo can say more than the picture shows. Depending on camera and settings the file holds:
- camera model, lens and, when the camera writes them, serial numbers
- exposure settings: exposure time, aperture, ISO, focal length, flash, metering
- date and time of the shot, with the time zone on newer cameras
- the GPS location with altitude and direction, if the device recorded it
- the software that saved the file and, if entered, name of the photographer or owner and copyright text
- a small preview image that is stored separately from the main image
Why messengers and social networks often remove it
Many messengers, social networks and image services remove metadata from uploaded photos or save a new copy of the image. This differs from service to service and can change. A photo that is sent as a file, by e-mail or from a cloud folder often keeps all of its data. What a file contains can be checked with this tool, and the EXIF remover removes the data.
Supported formats
The tool reads only the parts of the file that hold metadata, also from RAW files of more than 50 MB. Where the EXIF data sits depends on the format:
| Format | Where the EXIF data is stored |
|---|---|
| JPEG | APP1 segment with the identifier Exif near the start of the file |
| TIFF, RAW | The directories (IFDs) of the TIFF structure itself (TIFF, CR2, NEF, ARW, DNG, ORF, RW2, PEF, SRW) |
| RAF | In the JPEG preview embedded in the file (Fujifilm RAF) |
| CR3 | In metadata boxes of the file (Canon CR3) |
| HEIC, HEIF, AVIF | In an item of type Exif in the meta box (HEIC, HEIF, AVIF) |
| PNG | In the eXIf chunk |
| WebP | In the EXIF chunk of the RIFF container |
Limits
The MakerNote, a block with manufacturer-specific settings, is not decoded; only its size is shown. EXIF data can be edited with any metadata program, so it is no proof of when, where or with which camera a photo was taken. The clock of a camera can also be set wrongly. Fields that lie outside the file are marked as invalid.
Frequently asked questions
Is my photo uploaded?
No. The file is read in the browser, nothing is transferred to a server and nothing is stored. The only request to this site happens when the file names a lens: the list of lenses is loaded and compared in the browser, without any data from the file.
Why does my photo show no EXIF data?
Either the metadata was removed, for example by a messenger, a social network, an image service or an editing program that saved a new copy, or it was never written. Screenshots and many graphics contain no camera data. The original file from the camera or the memory card holds the complete data.
Why does the photo have no GPS location?
The camera has no GPS receiver, location was switched off for the camera app, the receiver had no signal, or the location was removed afterwards. Some cameras write the position 0° / 0° when there is no signal; the tool does not show a map link for it.
What is the 35 mm equivalent focal length?
The focal length is the real focal length of the lens in millimeters. The 35 mm equivalent converts it to the field of view on a full-frame sensor, so photos from cameras with different sensor sizes can be compared. The camera writes this value itself; not every camera does.
What does the MakerNote contain?
The MakerNote holds settings and data that the camera manufacturer defines itself, in a format that is not part of the Exif standard and differs from brand to brand. The tool only shows that it exists and how large it is. For a few brands the shutter count tool reads a counter from it.
Can EXIF data be wrong or changed?
Yes. Metadata can be edited without any trace in the picture, and a wrong clock or time zone in the camera leads to a wrong date. EXIF data is a hint, not proof.
Sources
- CIPA (Camera & Imaging Products Association) / JEITA: Exchangeable image file format for digital still cameras: Exif Version 2.3 (CIPA DC-008-Translation-2012)
- CIPA: CIPA Standards: DC-008 (Exif), current editions
- W3C: Portable Network Graphics (PNG) Specification (Third Edition), chunk eXIf
- Google: WebP Container Specification, chunks EXIF and XMP