English: The US Patent 4,214,814A, by Shuji Ogino, Toshinobu Ogura, Yukio Okano, and Akiyoshi Nakamura was filed by Minolta on March 7, 1978 (priority claimed from March 7, 1977) for a "Variable soft focus lens system". Embodiment 1 of this patent, depicted in Figure 1 with curvatures listed in Table 1, is redrawn here to scale, and matches the configuration (6 elements, 5 groups) of the lens marketed by Minolta contemporaneously as the 85mm f/2.8 Varisoft, but not the exact layout, indicating the production lens is based on the earlier patent (US4124276A).

As described in the patent, the lens is divided into two sub-lenses, marked A and B.

• Sub-lens A is a Tessar-based compound structure on the objective side of the lens
• Sub-lens B affects the amount of spherical aberration, with a larger air gap (as shown in the upper portion of the schematic) resulting in a large spherical aberration and a stronger soft focus effect. When the air gap is minimized (as shown in the lower portion of the schematic), there is virtually no spherical aberration.
• Both sub-lenses A and B are moved as a unit to focus the lens.

Compared to the prior patent (US4124276), the motions and mechanical scheme has been simplified.