Understanding EXIF: What it’s Good for

Today’s Post by Joe Farace

The Exchangeable Image File (EXIF) standard was originally established by the Japan Electronic Industries Development Association in 1995 to accommodate different digital image file formats and allow photographs made with one kind of camera to be played and viewed on another, different camera or 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 that photographs made with a Olympus Pen can be viewed on the LCD screen of a Panasonic Lumix G9, for example.

The EXIF standard defines file name standards and folder structures including how to store image and camera data. When a camera is set to capture and record a JPEG image file, it’s also recording EXIF file data using compression to store that additional photo data within the file.

EXIF metadata 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-related data such as compression mode, color space and number of pixels. You can read all of this header information externally using EXIF-compatible software, Like Adobe Bridge CS6 shown at right, that in turn uses it for image file management functions.

In addition to image data, EXIF includes thumbnails. Under DCF standards a typical thumbnail measures 160 x 120 pixels and 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 data the color space used. Color space describes the range of reproducible colors a camera can see, a printer will print, or a monitor displays. You can read more about Color Space in my post, “Color Space: The Final Frontier.”

 

 

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Barry Staver along with myself are co-authors of Better Available Light Digital Photography that’s out-of-print with new copies available from Amazon for $21.88 or used copies for giveaway prices, only $3.82, as I write this and while the book is a few years old it has plenty of real-world tips.