The 135mm F2.8 [T4.5] STF (SAL135F28) is a manual focus 35mm format compatible lens that is truly in a league of its own. With conventional lens design, it is extremely difficult to balance the demands of crisp, aberration-free imaging and smooth defocusing. But with this lens's unique STF (Smooth Transition Focus) design, these two conflicting goals are uncompromisingly achieved.
The lens consists of 8 elements arranged in 6 groups, with the fifth and sixth elements bonded together to create an apodization optical element that is mounted directly behind the aperture iris. It boasts exceptionally high contrast and resolution that ensure ultracrisp imaging, while the apodization optical element smoothes the transition between in-focus and out-offocus areas of the image to offer distinctively richer, more refined defocusing of the foreground and background.
Ideal for portraits, landscapes, and close-up work, the 135mm F2.8 [T4.5] STF also features a circular stepless T4.5–6.7 manual aperture mechanism to enable fine control of imaging and defocusing characteristics.