Jun Hirakawa

Mr. Jun Hirakawa is a Japanese lens designer best known for creating the Pentax FA 43mm Limited and FA 77mm Limited lenses during his time at Pentax.
Hirakawa said at the time that he regretted his "early retirement" from Pentax in 2010, around the time that Hoya acquired the company, and was subsequently hired by Tamron.
List of credited lens designs.
Hirakawa is credited with designing: