Konica Minolta is a provider of business solutions, offering technologies and performance materials. When the company was first founded they were primarily engaged in manufacturing cameras. Filters screw onto the front of lenses, still allowing you full funtionality of fully automatic AE exposure. Konica offered two attachment lenses in different strengths, both for 55 mm filter thread diameter. The earlier Konica attachment lenses where achromatic lenses made of two elements. The later variations were single-element lenses. Therefore, the earlier variations have a better image quality than the later ones.