The Exchangeable Image File (EXIF) standard was established in 1995 to accommodate different image file formats and allow photographs made with one kind of camera to be played and viewed on another, different device. It’s part of the Design Rule for Camera File Systems (DCF) to ensure compatibility between digital cameras and printers and allow image files to be exchanged so photographs made with a Canon can be viewed on the LCD screen of a Nikon.
The EXIF standard defines file name standards and folder structures including how to store image and camera data. When a SLR is set to capture and record a JPEG image file, it’s actually recording an EXIF file using compression to store additional photo data within that file.
EXIF supports storage of extended camera information within the image file’s header such as the time and date an image was made, device name, shutter speed, aperture, along with other capture data such as compression mode, color space, and number of pixels. You can read all of this header information externally using EXIF-compatible software that in turn can use it for image file management.
In addition to image data, EXIF includes thumbnails. Under DCF standards a typical thumbnail measures 160 x 120 pixels. Image editing programs such as Photoshop use EXIF data when displaying thumbnails in Bridge. Clicking on a thumbnail allows you to view all of the EXIF camera data so you can read specific details of how an image was captured, unlike when using film when you had to make physical notes!
One of the differences between the current version of EXIF and previous ones is the color space used. Color space describes the range of reproducible colors a camera can see, a printer will print, or a monitor displays.