A better comparison would be to say that they both fall into the same typographic category; they are both humanist sans families with a bit of geometric rigidity; both have been compared to the classic DIN type.
That overlay isn't particularly useful; it only shows that the two families have comparable metrics and tend to follow the letterform patterns common to the category. A better visualization would be a closeup overlay of some characteristic letters, or a pangram set in each.
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Looks like a straight up knockoff of Google's Roboto font: https://twitter.com/jm_denis/status/534802341770186752
Only big difference I can see is the 'Q'.
Only if Backbone is a knockoff of Ember.
A better comparison would be to say that they both fall into the same typographic category; they are both humanist sans families with a bit of geometric rigidity; both have been compared to the classic DIN type.
That overlay isn't particularly useful; it only shows that the two families have comparable metrics and tend to follow the letterform patterns common to the category. A better visualization would be a closeup overlay of some characteristic letters, or a pangram set in each.
http://en.wikipedia.org/wiki/DIN_1451
At first glance, they look very similar. However, in use there's a big difference between the two.
San Francisco is squarer which makes its x-height seem higher. The minor variations in lettering make a massive difference when used in application.
100% not a knockoff of Roboto. They're really, really different.