What's this EXIF technology people used to study Trump photos?
Digital cameras can store lots of information about where, when and how photos were taken.
Stephen Shanklandprincipal writer
Stephen Shankland has been a reporter at CNET since 1998 and writes about processors, digital photography, AI, quantum computing, computer science, materials science, supercomputers, drones, browsers, 3D printing, USB, and new computing technology in general. He has a soft spot in his heart for standards groups and I/O interfaces. His first big scoop was about radioactive cat poop.
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I've been covering the technology industry for 24 years and was a science writer for five years before that. I've got deep expertise in microprocessors, digital photography, computer hardware and software, internet standards, web technology, and other dee
President Donald Trump's case of COVID-19 gave an obscure photo data technology called EXIF its 15 minutes of internet fame as people started scrutinizing photos taken of him this weekend at Walter Reed hospital. But what exactly is EXIF?
In short, it's a standard way cameras can embed metadata within a photo file. That data can include the camera model that took the shot, what exposure settings were used, where a photo was taken and, most pertinent in Trump's case, the time the photo was taken.
People can alter EXIF data, so it's not a certain indicator of photo attributes, but it's often accurate. It's one of the examples of how ordinary living generates a trail of data wherever we go and whatever we do. Our digital lives are convenient but can reveal more about us than we might like others to know.
Here's a look at what EXIF is and isn't, and what you can and can't do with it.
Metadata is data that describes other data. In EXIF's case, that means data about a digital photo. That can include information like shutter speed, exposure time, camera model, camera serial number and a small thumbnail version of the photo. Cameras initially record EXIF, but photo editing software can edit it more, for example adding latitude-longitude location coordinates.
How do you read and alter EXIF data?
Mainstream photo editing software like Adobe Photoshop and Lightroom can read EXIF data. They also combine EXIF with other metadata types useful for recording information like photo titles, captions, keywords and copyright. Specialized tools like ExifTool also let you scrutinize and change metadata details.
Photo editing software often adds new EXIF data reflecting that a photo has been edited.
No. It's not an unalterable record. In addition, camera settings can be tweaked or set incorrectly. EXIF in your mobile phone photos will update when you change time zones, but conventional cameras usually have to be reset manually. Similar timestamp problems take place when daylight saving time begins or ends.
That said, most people don't fiddle with EXIF or other metadata, so EXIF can indicate useful information about a photo even if it may not be certain proof when a photo was taken.
How can you use EXIF?
EXIF data can be useful in many ways.
Lots of software handles metadata even when you don't know it. When Apple Photos or Google Photos lists your photos by date, that's thanks to EXIF data. You can also use EXIF to search for photo attributes.
EXIF also can be useful for photography enthusiasts. Smugmug's Flickr photo sharing site publishes EXIF data so photographers can see parts of the recipe that created a photo, like shutter speed, ISO sensitivity, and lens and camera model.