Designed to provide a wealth of control over out-of-focus quality and to enhance bokeh, the Laowa 105mm f/2 Smooth Trans Focus Lens from Venus Optics is a short telephoto prime designed for full-frame Pentax K-mount cameras. The unique optical design incorporates an apodization (APD) element, as well as two separate diaphragms—8- and 14-blade—to provide separate adjustment over the bokeh as well as the exposure and depth of field. This APD element functions as a radially graduated neutral density filter, and as such limits the light transmission to a T-stop value of 3.2, while permitting the depth of field and selective focus qualities of a true f/2 design.
Alongside the unique attributes of the APD element, the lens also incorporates three low dispersion elements and one extra refractive index element to control chromatic aberrations and color fringing, as well as produce a great deal of overall clarity and sharpness. The lens is also characterized by its manual focus, manual aperture design, that provides a wealth of control over focus and exposure to benefit working with the APD element.