Bokeh similar to petzval lens gives with a fully open aperture and maximum defocusing of the background with obligatory backlighting. Example: the distance to the subject (portrait) is 1.5 m, the distance to the background (flowers) is 3.5 m. The background (flowers) is illuminated by lanterns. . Aperture f=2.
The result is a portrait in the center of the frame, and swirling bokeh along the edges of the frame. Little digital processing is required to enhance sharpness.
The lens is designed to work on SLR cameras with a working distance of at least 55mm, and on mirrorless cameras with an extension adapter that increases the working distance to 55mm.