SB N5 vs N7?
Strange the rest of the previous post was hidden under the signature ...
--> Distance = Guide Number / f/stop
N5 at ISO 100 --> 8.5 / f3.5 = 2.4 m
N7 at ISO 100 --> 18 / f3.5 = 5.14 m
Let's say when using the 18.5mm prime at f/1.8...
N5 at ISO 100 --> 8.5 / f1.8 = 4.72 m
N7 at ISO 100 --> 18 / f1.8 = 10 m
N5 at ISO 800 --> 24 / f1.8 = 13.33 m
N7 at ISO 800 --> 51 / f1.8 = 28.33 m
N7 has generally a little more than double the reach of the N5 !
BTW, another so far unnamed point is, that the N7 comes also with the SW-N7 Wide-Flash Adapter, which might give it some advantage for wide angle flash shots. This could be handy when making group people shots or the like, since it expands the illumination angle and diffuses the light.