See and Buy this product on Amazon.com store (affiliate):
Sony Alpha Blog Although the build construction is very good like all Voigtländer, performances are really below average vs modern lenses. Sharpness: soft wide open , good around F2.8 and only very good at F5.6-F8. Corners are being soft and only reach the good grade around F5.6. Heavy lens fall off wide open, reducing around F2.8 but still present. Glow effect at F1.4. Strong Flare. Noticeable distorsion.