EXIF 101: What’s it Good for?

by | May 7, 2020

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 kinds of digital image file formats and allow photographs made with one kind of camera to be palyed 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, for example, can be viewed on the screen of a Panasonic Lumix G9, for example.

The EXIF standard also 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.

Within the image file’s header, EXIF metadata supports storage of extended camera information, 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 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 or have a really good memory.

One of the differences between the current version of EXIF and previous ones is data on 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.

How I made this shot: This femme fatale style portrait of my original muse, Tia Stoneman, was made using window light in the living room of my former home. No reflector or speedlight fill was used. It was, as you can see, made with a Canon EOS 5D (Mark I) with my favorite but now discontinued EF135mm f/2.8 (with Soft focus) lens with an available light exposure of 1/125 sec at f/4 and ISO 320. For some reason the color in the original was off, perhaps due to underexposure. Most of the underexposure was corrected with this technique but the color still wasn’t right, so I converted the image to monochrome with Silver Efex Pro.


 

New copies of my book Creative Digital Monochrome Effects are available from Amazon for $33.65 with used copies starting around two bucks, way less than your next coffee at Starbucks. No Kindle copies are available.