The 28/3.5 was introduced in March 2002 - discontinued in April 2007. It is the smallest Voigtlander lens. It uses 7 lens elements in 5 groups, and has a 39mm filter size. The 28/3.5 also accepts the optional LH-1 square lens shade. Notice the convex front element. Weight is 163 grams. Close focus is .7 meters.