There are many manual lenses above 28mm which work quite well on modern cameras like the Alpha 7 but not that many wide angle lenses perform good enough on modern cameras.
The Canon nFD 2.8/24 is one of the sharpest, affordable wide angle lenses and I think it can be a good solution for budget-oriented Sony Alpha 7 users.
A German version of this review can be found on phillipreeve.de.