Understanding EXIF Data

Author: Gaurav Birla August 26, 2010 No Comments

EXIF data helps photographers achieve better exposure and composition in their digital photos. The IPTC section is part of most image management strategies.

Exchangeable Image File or EXIF is one of the big advantages of digital cameras as it stores all the camera settings as part of the image file. Not only is this available when reviewing images in the camera, but also because it is part of the image file it goes with the image when it is transferred to a computer for editing and storage. This does away with the film practice of making detailed notes of the camera settings in a notebook, leaving no doubt which data belongs to which image.

Not only can the camera settings be read on the computer with an EXIF reader there is a place in the EXIF data for photographers to add notes and keywords for managing images using an EXIF editor. These reading and editing functions are usually part of most good photo software packages such as Adobe’s Photoshop and Bibble Pro.

Exposure Data

406px-Konqueror Exif dataThe ability to review exposure settings and the image in the camera or on the computer is a valuable learning tool for the professional as well as the novice photographer. This allows photographers to take a short series of test shots, altering one of the camera settings for each shot, say try different aperture settings and then immediately review on the LCD screen where the histogram display is an important tool in determining exposure. A more detailed examination and comparison is possible on the computer where the images can be viewed at a large size and placed side by side on the screen to see any subtle differences resulting from the alternative settings.


This effect of settings on composition is usually something reviewed on the computer where the effect of lens focal length and aperture on field of view and depth of field, and how the choice of shutter speed affects the portrayal of moving subjects. For zoom lenses the EXIf data usually shows the actual focal length used. This is as a basis for using a different lens in future, or helping decide on the focal length for a new lens. If the same focal length is regularly used on zoom a high quality prime lens could be used instead.

When and Where

exifApart from pure cameras settings the EXIF data also contains time, date and in some cases GPs location for the image. This is useful for sports photographers t help identify subjects. For example in thoroughbred horse racing the horse numbers and jockey’s silks are often the same in different races. By consulting the image time and referencing this to the race program determines which race it is and hence which horse carried that number or colors.

For travelers date and time details help determine where the image is from. Some cameras even have satellite position (GPS) devices built in to give an exact location for the image, a handy feature for those trekking off the beaten track.

Management Information

23256-gogo-exif-image-viewer-pro-activex-ocxThis is based around the IPTC Exif data (International Press Telecommunications Council) where photographers add notes and keywords to the image file. As suggested by the name this is a commonly used standard for the press photos, and has spread to common use for all professional images and their software systems. Typically there are fields for image title, caption, photographer details, usage conditions, and a collection of keywords for the image. Some stock photography library systems read this IPTC EXIF data from the image file rather than the photographers having to enter all the information again.

The keywords are important for searching among a large photo collection looking for a particular photo. Adding keywords to image files give s application such as Adobe’s Photoshop and Lightroom some text to search for. Even windows Explorer, the humble file management tool in Windows Vista, will search the IPTC text fields. Windows Explorer is also an EXIF viewer and EXIF editor. For photographers this offers advantages in recording details of photographs of family memories or holidays for sharing, or handy when looking back years later.

Use the EXIF data to Move from Scene Modes

This can give photographers the confidence to take control of their cameras. Many photographers are not sure where to start with aperture and shutter speed settings when contemplating a move away from scene modes. The exposure settings from the programmed scene modes usually provide a good starting point as they take into account the capabilities of your camera.

After taking a landscape picture using the appropriate scene mode, view the EXIF data and see what digital camera settings the programming chose to use. Then apply these settings to the semi-automatic exposure mode, Aperture Priority (Av), and experiment with different aperture settings, the shutter speed will be automatically adjusted for a reasonable exposure while the depth of field will vary.

With the EXIf data the settings from all your photographs can be viewed on the computer to give an idea of how the scene modes change the camera settings over a wide variety of scene types.

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