Tom if you are in the path of totality, it is quite safe to view the TOTALLY obscured sun with the naked eye. Indeed, don't bother trying to take photos of it, just lie back and enjoy the spectacle and count yourself incredibly privileged to be able to see one. Don't take a chance of missing any of it due to fiddling with a camera. A small cloud could block the view at a crucial moment. (If you are a professional photographer making your livelihood from astronomical images that is a different story.)

Until the sun is 100% TOTALLY obscured by the moon there is not much to see really -- it doesn't even get very dark -- so there is little point in trying to look at it safely. All you see is a bite being taken out of the sun that gets progressively bigger. We in Toronto were under a (rare) annular pseudo-total eclipse several years ago and while it was cool to see a narrow ring of sun around the moon, the residual brightness was, as expected, enough to obscure the corona -- and, I add, not safe to look at.

So just sit with your back to the sun as the eclipse progresses and resist the temptation to glance up. In the last moment before totality -- someone in the gathering will have equipment to see it coming -- turn toward the horizon
and watch the moon's deep shadow racing toward you across the landscape as the earth rotates under it. When it gets dark and the stars come out, look up and enjoy. Be prepared to look away the instant that Bailey's beads re-appear, ideally a few seconds before, as the brightness rises rapidly from there. And then it's over.

Oh, and be sure to visit the bathroom well before totality. There are stories of people missing the whole thing on account of being stuck in a long queue inside somewhere.

*(Much of this advice comes from the Hamilton Amateur Astronomers who are organizing a trip to Missouri which I am going to miss )