Sharp edge to edge, good color rendition, and fast enough.

Pros:-Internal focusing-Sharp edge-to-edge-About as ultra-wide as you'll get without ultra

I shot at 1/30th handheld and got sharp as an edge images across the frame

This is a SHARPER lens edge to edge wide open

The edge to edge sharpness over the whole frame, even at F/4, is impressive

The wide angle does not distort or stretch the edges like others do.

What I loved about this lens was the light weight at 1.3 pounds (615g) for easy use in travel and hiking