The often disregarded Voigtländer Ultron 28mm f/2, at f/5.6. No APO, no ASPH., just nice glass ... To be honest, my Elmarit-M 28mm f/2.8 (non-ASPH.) may be contrastier and appear sharper, but I'm really pleased by the rendering of the Ultron in most cases ... smooth, but certainly not mushy or, at the other extreme, harsh. It doesn't hurt that it's sharp wide open, either. Certainly not as shrug-worthy as some seem to think.