Sony SAL-135F28 135mm f/2.8 (T4.5) STF Telephoto Lens for Sony Alpha Digital SLR Camera Smooth transmission focus system for pleasing effect Apodization lens element smooths out-of-focus areas Subjects stand out vividly against smooth, even backgrounds Manual aperture ring adjusts from T 4.5 to T 6.7, manual focusing with comfortable wide focus ring Circular aperture gives spot light sources a circular shape