With the recent passage of the time boundary separating Standard Time from Daylight-savings Time, a reminder posed on the Yahoo group of the Minneapolis Photographic Society caused me to think about time and Digital SLR cameras.
“Now I am in danger of being
accosted by the EXIF police.”
In the days of film, prints were were stamped with the develop date on the back-regardless of when the picture was taken. The time stamp indicated the completion of a roll. There may be pictures hidden there since last Christmas but we accept the ink on the back of the print as a valid representation of the time at which they were exposed.
Digital files capture the moment and second of every photograph and store it electronically for posterity. This is a great boon to photographers who need to know exactly when a photo was taken for a variety of reasons. They may want to duplicate the time and date conditions or they may need to know how old somebody was when the photo was taken, or they may just need to get events in the proper chronological sequence. Storing the date in the metadata coupled to the image is a great advantage.
The entire system, however, is based upon the premise that your camera has been set correctly to start with.
When we open our digital camera for the first time, the instructions, perhaps on-screen instructions have us set the date. This often goes unheeded. My father-in-law still sends me picture dated several years ago even though I know that they were taken last week. His accuracy of his date is within several years of time and I guess that is good enough.
Some cameras will reset their clocks to your computer’s clock upon connection to a USB port. All of my DSLRs will do this. In fact, when I plug in, they tell me and then ask me if I want to update my camera to the computer’s time. I keep my computer clock accurate so I say, “Sure!”
Here’s the issue. I don’t often plug my camera’s into the USB port. I extract my images from memory cards plugged into card readers. Thusly, when DST or CST rolls around, my camera suddenly becomes off by an hour. Now If I were to look at a photo from last year and decide that 6:30 PM would be the time to shoot tomorrow, it isn’t an issue-unless they move the date for the time-change like they did this year! Admittedly this is a small issue but it got me thinking about larger issues.
If I travel to San Diego and shoot pictures two time zones away, I don’t reset my camera or my computer to local time. This means that the time my camera is reading is not the time at which the photo was taken-locally speaking. Sunset will be two hours late according to the EXIF Data. If you look at the picture at the beginning of the article, you will see not only am I off the two hour time zone difference but I have AM and PM screwed up too!
Now I am in danger of being accosted by the EXIF police. I share images with many groups and when I tell someone, “Look at this lovely San Diego sunset,” the EXIF police dig into my file and say: “Whoa! You shot this at sunset? The sun doesn’t set at 8:13 in the morning in San Diego, it is rising and it doesn’t rise over the Pacific neither.”
True story. I have actually had people question the veracity of my images claiming I faked them or didn’t shoot them where I said I did all because the time stamp from the camera didn’t jive. See the above email from a gentleman who knew where I stood taking the picture and misinterpreted what he saw with the EXIF data he extricated.
Save yourself some trouble. Set your camera’s clock today. And when your computer reminds you that a time change has occurred, remember to plug your cameras in and reset them too. Whether you want to adjust for travel time-zones is up to you but get AM/PM right if nothing else!
Rikk Flohr © 2008