Augmented reality is the talk of the town at F8, but that doesn't mean you'll see the tech any time soon.

As Mark Zuckerberg made clear in his lofty keynote talk Tuesday, AR is the future. But he left it to Michael Abrash, the chief scientist for Oculus, to bring us all back down to Earth on Wednesday.

In the F8 day-two keynote, Abrash told a crowded room full of developers and press that real, always-on augmented reality glasses are at least five years away. And that was his early estimate. He also said it's possible we're 10 years out.

Or maybe more.

Today's AR technology is at the point of computing in 1971, he said. In other words, it's primitive.

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This takes a bit of the air out of Zuckerberg's big speech, where he proudly declared that Facebook is making the camera the next AR platform. The entire thing seems a tad less exciting, after all, if Zuck's own Oculus chief scientist makes an analogy between the current state of AR and the very first graphical user interface.

But just because AR glasses are perhaps a decade or more out, that doesn't mean augmented reality will remain a dreamy hypothetical. Even in the early form demonstrated at F8, it's a powerful tool — and one that Facebook clearly intends to ride head first straight toward the augmented future.