PrimoPlan is five elements four grorps lenses.　The Meyer Co. produced PrimoPlan as a high-speed lens for the SLR camera. Primoplan we often find in the market has Exacta (35mm format) mount. There are 58mm and 75mm (80mm for the medium format camera) made for Exakta. 　We rarely find the lens for Leica screw and Contax CX. 　Regarding Meyer's catalog at that time, we only see PrimoPlan as the standard lens for Exacta camera. 　It is said that PrimoPlan was designed to compete other SLR lenses such as Zeiss Biotar 50mm F2 or Schneider Xenon 50mm F2 because the F number is a bit (0.1) faster than its competitors. Now, please enjoy Primoplan (Lens) of the Meyer Co.