When we refer to time we can say “It’s 2 PM”. This is easy enough to understand. It is early afternoon at our current location.
Digital cameras record date and time in a similar manner. When you load a photo onto your computer, you can see the time as recorded by the camera: 2 PM. The computer, however, cannot make much sense of this information. It is missing an important clue: location or time zone. For all it knows, “2 PM” could mean early afternoon in Hawaii or early afternoon in New York. A 6-hour difference!
What’s more, the camera clock may not actually have the correct time. You could have forgotten to set it as you traveled through time zones. Your photo of the New York night sky could indeed show a “2 PM” camera time.
We thus face two tasks:
- Set the correct time on the photo. E.g. “2 PM Hawaiian time”
- Make that time look “right”. E.g. “8 PM New York time”
Let’s walk through the process.