At the suggestion of Moler's Camera in Wichita, I recorded the serial numbers of my gear. Turns out I have 31 lenses. As I cannot read Cyrillic, I had to look up one of the lenses I rarely use, the Soviet-era Industar-61 L/Z 50mm f/2.8 I have adapted to Canon. While I was looking up its specific nomenclature, I ran across an article by a Malaysian photographer who marveled at its unique bokeh, yet provided no examples. He did however mention the piece which had been alluding my own results; f/5.6!
So after a green-screen shoot due to horrific winds all day long, I went out afterward to shoot the backgrounds separately, dragging along the Industar-61. I have to say, I was not disappointed!