Allready at 1.8 high contrast and sharpness. The Nikon- and Canon-likes reach this level at f: 4 or 5.6. You don't need to stop down for a lot of higher contrast and sharpness. Ideal for setting subjects and objects free in cities and landscapes and to use depth of field in a creative way.

See above; Build like a tank

SLRgear Review February 23, 2009 by Andrew Alexander The Sony 135mm ƒ/1.8 ZA lens was introduced in October 2006, shortly after the debut of the Sony alpha system earlier that year.