The switch between “Daylight” and “Standard” time doesn't universally occur across the globe. More than 100 countries never change to “Daylight Time”, and more than a few countries switch between the two on different dates than other countries.
In Mexico the switch between “Daylight” and “Standard” time can be very confusing for travelers. Mexican border cities near the U.S. typically swap their “times” on the same dates as the U.S., but the remainder of Mexico changes in April and October, not March and November.
For most of those living or traveling in the U.S., they will set their clocks, watches, computers, cameras, and other devices with internal clocks, forward one hour on Sunday.
Many ask if it matters that one's camera is set to the correct time of day. For me, it matters.There are several reasons having one's camera set to the correct time of day and date is important.
1. I “geotag,” embed the longitude and latitude in virtually all my photos. As a travel photographer, sometimes my notes aren't quite complete, and I'm not exactly sure where a particular image was made, Going back to the images later sometimes I'm not quite sure precisely what the scene is showing. To the rescue comes the embedded GPS data, in each of my images. That data will allow me to pinpoint on Google Earth and other mapping programs where I stood and in which direction I was pointing when making the image.
When I spent a number of weeks shooting in Morocco, for example, there were several times I was able to capture some wonderful images, when we stopped in the middle of nowhere, while traveling to our next destination. Via the GPS information embedded in my images I was able to pinpoint where each image was made.
Having the precise time in my camera facilitates geotagging accuracy, especially if I have to use my GPS data file backup which requires date/time synchronization.
2. Speaking of notes, keeping a “written” record of your shooting can be very helpful later on, in part, as mentioned above. A friend I know uses written records and he “time stamps” each record. My notes are generally voice recordings. I dictate notes into my iPhone about the shoot as I go along. At times if I'm with a guide, I'll record the guide. Sometimes I also record written information which I type into my iPhone while shooting. All the notes are “time stamped.” By having my images correctly “time stamped” it becomes easy to associate the notes with the correct images.
3. I periodically use more than one camera during a shoot for a variety of reasons. For example, it enables me to quickly move from a wide angle lens, to a telephoto lens without taking the time to swap lenses and miss an important shot, if the lenses are on separate camera bodies. Also, there are times when I'm in a difficult environment, such as in a desert with blowing sands, where swapping lenses isn't an option. If I opened the camera to change lenses I could easily get sand blown into the camera damaging it.
When using more than one camera, it's extremely useful to know the order of the images made. You can't do that unless each camera has the right date/time, so you can refer to the date/time exif data in each image, and determine the order the images were made.
4. I periodically review my images. It's very helpful to have the time of day accurately saved in the images when reviewing them. You can better revisit your thought process during the review if the correct date/time are embedded in the images.
So, if keeping accurate time in your cameras is important to you. Don't forget to reset your camera's clock this coming Sunday, March 12, when you reset all your other clocks in your various devices.