Sorry, that calculation was way off. When I looked at my write-up on the screen, it just didn’t look right.
Looks like I’m off by a factor of a thousand (swapped meters for millimeters at one point).
It’s actually 0.21 pixels per ridge spacing at one meter, which puts it out of reach of the iPhone 7 camera. Way out of reach, even if you don’t count the dynamic range issue.
I should have double-checked.
That’s OK.
But you do know that the day is coming when that will be possible.
I don’t put much out of the reach of technology any more.