The Value of Metadata
Metadata, in it’s most fundamental definition is simply “data that provides information about other data”. In our case, it’s information about the photographs that we capture. This includes information about the image itself and also the camera that captured the image, where it was photographed and much more.
Metadata has been around a long time even though the first use of the word itself dates back only to 1983. For those old enough to remember card catalogs in a library - well, that was metadata too.
The metadata related to photographic images is extensive and the topic can get quite detailed. For today, we’re taking a 30,000 foot view of metadata starting with “why does it matter?”
The metadata in your image file provides many benefits. For example, the camera settings that are stored in the metadata help your image editor render a proper image. You can also include your personal copyright information in an effort to protect your image. Information about the image, such as keywords, a description and title can also be included. All this helps identify and organize your image library and supports archiving and preservation of the images.
When working in Photoshop or Lightroom you may find metadata organized into two main groups. IPTC and EXIF.
EXIF is an acronym for Exchangeable Image File Format, a standard created by the Japan Electronic Industries Development Association in 1998. Exif metadata covers a wide spectrum of information including date and time, camera settings, a preview thumbnail image, descriptions and copyright information.
This is the data you’ll check to see your shutter speed and aperture settings, as well as focal length, metering mode, ISO and other camera settings.
Even though EXIF data is quite extensive, it is an old standard that has not kept up with technology. It lacks crucial support for the extensive volume of data that is generated by today’s digital cameras. For example, the EXIF standard defines color depth as always being 24 bits, yet some newer cameras capture color at 36 bits per pixel. It’s for this reason that manufacturers have been pushed to develop their own proprietary standards that are now found in their RAW files. (But that’s a whole other topic so let’s not go there.)
IPTC is an acronym for International Press Telecommunications Council. Although IPTC is the acronym to commonly refer to a specific subset of metadata, the actual file structure of this data is called the Information Interchange Model (IIM). IPTC data is widely accepted as the standard for news and commercial photographers. Information such as the photographer’s name, image headline and description are included.
IPTC also includes the important copyright information. Whether your a professional or an amateur photographer, you should include your copyright information whenever you download your images.
As you can see, there is a lot of metadata that is automatically generated when the image is captured and processed. This information can be very helpful as you develop your photographic skills and critically evaluate your images. For example, let’s say you have an image that isn’t sharp. You can use the metadata to help determine why. Is your shutter speed too slow for the subject?
What about focus? Did you know that in all that metadata is information about how your camera focused on the subject, including identification of the exact focusing sensor(s) that were used. This information can be very helpful in isolating focus and sharpness issues but it can be hard to find. In fact, you won’t find it in Lightroom or Photoshop.
To access some of this type of metadata, you need to use software from the vendor. In my case, I can use the Canon Digital Photo Professional software that comes with the camera. From within the Canon DPP I can access the focus information and other data unique to my camera. This would include the Canon Picture Styles too.
Some of the most useful metadata is that which you can add yourself. Take advantage of your editing software to add keywords, image titles and captions. This information can be very helpful when looking for specific images in the future.
Most importantly, be sure to add your copyright information to your images too. In Lightroom - and in other software - this can be done when you download your images. Look for the Apply During Import tab when importing your images.