When taking a digital photograph, many cameras capture a lot of good information that can help you learn what kinds of modes were used on the camera, allowing you to get a sense of what lens was used and what settings were used in the photograph. This information is called the EXIF (Exchangeable Image File) information.
In some cameras, you can even embed a copyright right into the EXIF, so that when someone views the information available to them, you can have them see who the original creator of the photo was as well.
There are a number of cool plugins that can give you the information without having to download the file to study it further. One of my favorites is Opanda IExif for Firefox, a plugin that is embedded into your right-click menu on Firefox. When you right click on any image on a web page, you will get the option to view EXIF information, if available, like this:
When I click on the “View Exif/GPS/IPTC with Exif” option, the following information is available to me:
As you can tell, this is just a subset of the information that the IExif information provides. If you took a look at all of it, you would know that I used a Nikon D70 camera and did some touchups in Adobe Photoshop CS2 on September 12th, 2005.
But the most important information a photographer can take from the image is shown in the screenshot above, which I will explain here:
- Date Time Original: While this is not necessarily important for most shots that you’ll take, in this case, it showed that the photo was taken at night and the light available to me was minimal. Consequently, I had to use the following information:
- ExposureProgram: Shutter Priority. I chose to have the camera automatically adjust its settings based on the amount of time the shutter was open for the shot, especially given that the photo was taken at night. In other words, I manually adjusted the amount of time I wanted the camera to photograph for (shutter), and it automatically adjusted the aperture setting. (Other pertinent “exposure” modes are Aperture Priority or Manual Mode.)
- ExposureTime: 8″means that I took an 8 second exposure. Since it was dark, I needed to keep my shutter open as long as possible for enough light to hit the lens. Naturally, I had a tripod with me.
- F Number: This is also known as Aperture. Even though I shot in Shutter Priority (and the the aperture was randomly assigned), the camera understood that I needed a wide enough aperture (while not too wide to give too much depth-of-field) to achieve the shot I was aiming for. In the specific photo (the WTC Memorial on September 11, 2005), I used what Bryan Peterson, renowned author of the world-famous book (and a must-read for new photographers), Understanding Exposure (aff), calls a “who cares” aperture, because I was primarily interested in the lights in the distance (or “infinity”). The particular aperture opening for the amount of light that was available at the time is important, because if I shot at F22 (a very small aperture), I would have ended up having to hold the shutter open a lot longer, which was actually tough for the shot I took since so many people were walking by!
- ISOSpeedRatings: This is simply the ISO I shot with at the time. I used ISO 200 (the lowest on a D70) which was perfectly fine because I was using a tripod.
You can also see in the EXIF information that I also embedded the copyright message into the photo.If you cannot, for whatever reason, use Opanda IExif, I recommend Irfanview, which I have written about earlier. Irfanview also displays EXIF information. Simply open a photo and then press I (for Information) and then E (for EXIF), or go to the Image menu, select Information, and click on EXIF. You will see a similar amount of information:
I touched upon earlier that this information is not always available. Some photographers, unfortunately, don’t want to share how they achieved a certain shot. EXIF information is generally stripped when a photographer uses a program like Photoshop and chooses to “Save for Web.” While that does make the photo a lot smaller, the EXIF information gets taken away as well by default. Also, the EXIF information is helpful, but it won’t take into account other equipment that was used, such as strobes and the like. It is definitely useful information but should not be used by itself to “reproduce” another’s image technique.
Since I’m primarily a Windows user, I don’t know what EXIF applications are available to Mac users, but I’d love to know if there are any. Can someone provide me with some tools in the comments?