Minolta STF 135mm f/2.8
|Minolta 135mm STF|
image by seagr112 (Image rights)
The STF 135mm f/2.8 [T4.5] is a full-frame lens which was originally produced by Minolta, and is currently produced by Sony. The lens features a six group, eight element construction. It is manual-focus only and is the sole lens currently produced by Sony which features an aperture ring. The lens currently retails for $1,400. It has a 72mm filter size and weighs 730g.
Smooth Trans Focus
STF stands for Smooth Trans Focus, which smooths the transition between in-focus and out-of-focus areas. The lens uses an apodization filter which improves bokeh. The lens features one nine-bladed and one ten-bladed aperture. They are both circular. The nine-bladed aperture, measured in f-stops, controls the depth of field, whereas the ten-bladed aperture, measured in t-stops, controls exposure.
- A Kurt Munger review of the lens, with examples of the bokeh produced by it.