What's the difference between 59.94fps and 60fps?

What's the difference between 59.94fps and 60fps?
The Transition to Digital e-mail bag recently included a message from a reader asking if there is a difference between 59.94 and 60 fields or frames per second. The reader has five HD cameras, all from a single major manufacturer, three of one model and two of another. One model specified a video output frequency of 59.94fps, while the other was specified at 60fps. The manufacturer told the reader that 59.94 and 60 are the same. Research and a number of interesting conversations with industry experts revealed information you may find surprising.

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