Spring Forward, Fall Back: Remember to Set Your Camera's Clock Too
For those who live here in the United States, Daylight Saving Time ushers in the first signs that spring is right around the corner. It also ushers in the first of two annual rounds of changing all your clocks. This usually happens the first Sunday in April, but thanks to the Energy Policy Act of 2005, DST now comes a bit earlier on the second Sunday in March. This means that by the time you read next Sunday's PhotoTip article here on Earthbound Light, you should have already changed your clocks at 2:00 a.m. on March 11. And if you are shooting digital now, don't forget to change the time on your camera too.
This may be something you're going to have to get your camera manual out to figure out how to do. On my Nikon D2x, changing the time is done using the World Time option on the Setup Menu. You can change the time zone using a map by selecting your location on a map of the world, but Daylight Saving Time can easily be toggled on or off directly from the menu itself.
If you don't remember to change the clock in your camera, the embedded EXIF date on all the images you shoot will be wrong. While this may be a bit of a bummer when you finally realize you forgot, it isn't the end of the world. Many EXIF editing tools allow you to change the date in images after the fact. My favorite tool for this sort of thing is EXIFutils, a set of command-line utilities for manipulating EXIF data. The included EXIFDATE command can easily add or subtract a set amount of time from every image in a folder.
And don't forget that you'll need to change your camera time if you travel and change time zones too. And again when you get back home.
Most computers and many consumer electronics are smart enough these days to set their own clocks, but I'm not aware of any cameras that are that smart yet. With the law change effective this year, many clocks that you used to be able to let adjust themselves will take manual intervention this time around anyway. Both Microsoft and Apple have been kept busy issuing fixes for any DST issues their software may have. Other clocks change themselves using built-in rules that are not updatable. Not only will you need to change these yourself on March 11, you may need to double check that they don't change themselves a second time a few weeks later when the time used to change.
On a related topic, have you ever wondered just how your camera keeps time when you remove its battery? Some simply have a capacitor to hold enough charge temporarily while you put in a new battery, but many have a small extra battery specifically intended to keep the clock from forgetting what time it is when the main battery is out.
On my Nikon D2x, there's a small lithium CR1616 watch battery hidden underneath the main EN-EL4 battery. It should last around four years and when it's time to change it the word "CLOCK" will appear on the top LCD panel and functions such as the interval timer that depend on the clock will stop working. After removing the EN-EL4 battery, a small flashlight should be all you'll need to locate the cover for the clock battery compartment. If you have a new CR1616 on hand before you remove the old one, the camera should retain the time while you put the new one in. If not, you'll get to reset it, just as you have to for Daylight Saving Time.
This fall, we get to go through the whole time-change ritual all over again, but in reverse. When Daylight Saving Time ends, we get to set all our clocks back one hour. Beginning this year, that happens a bit later than before. It now falls on the first Sunday in November, so mark your calendar for November 4, 2007 at 2:00 a.m. local time.
The European Union undergoes a similar time change, with Summer Time beginning the last Sunday in March at 1:00 a.m. UTC (Greenwich Mean Time). It ends the last Sunday in October, also at 1:00 a.m. In a move at least somewhat more sensible than what we do here in the US, clocks change at the same moment all across the EU, regardless of the local time zone.
Many other countries have some equivalent to Daylight Saving Time too. Two good lists can be found here and here.
Update 03/05/2007 - Rather than deal with changing the time at all, a couple of readers have suggested setting the camera time to UTC (Greenwich Mean Time). Especially if you do a lot of travelling, this may be an option. If you still want to convert to local time when you get back home, use EXIFutils, EXIFTool or another editor to adjust the time in your images after the fact. Taking a picture of a local clock or your already adjusted wrist watch at the beginning of each shoot can give you a reference for what local time was later. I think I'll stick with setting the camera time myself though. If I have to contend with adjusting the clock on the microwave oven and in the car, I figure I can do the cameras as well. Of course I could always set the microwave to UTC....
Update 03/06/2007 - One other quick note: the correct spelling is indeed "Daylight Saving Time" rather than "Daylight Savings Time." Although commonly said that way, there is no "s" at the end of "Saving." Really there isn't.
Update 03/17/2007 - Be sure that all your software programs support the Daylight Saving Time change too. And I mean more than just Windows and Mac OS. Two of the date-dependent programs I rely on are Heavenly Opportunity for sunrise/sunset calculations and WXTide for tide tables. Both are great programs, and both have recently issued updates for DST. You can find the latest version of Heavenly Opportunity here, and the update for WXTide here. And if you aren't already familiar with both, why not download take time out to give them a try?