Having just purchased the 30mm Sigma I thought I would compare it against the 19mm. Just some basic thoughts. 1- Shorter. Suprized me that the 30mm is shorter than the 19mm. 2- Lens hood not included. The 19mm came with a nice, reversable lens hood. The 30mm does not, and the lens hood from the 19mm does not fit. 3- As far as images, both seem fairly equal, but I don't get too carried away.