The Minolta MD Rokkor-X 50mm f/1.7 lens was primarily produced from 1977 until the early 1980s, when Minolta began phasing out the "Rokkor" branding on lenses destined for the US market. Some variations of the plain "MD 50mm f/1.7" (without the Rokkor-X designation) continued to be manufactured as late as the mid-to-late 1990s in conjunction with the X-370 and X-700 cameras. Focal Length 50mm Maximum Aperture f/1.7 Lens Mount Minolta MD Mount Focus Type Manual Focus (only) Filter Size 55mm (as labeled on the lens in your image) Construction 6 elements in 5 groups Minimum Focus 0.45m (approx. 1.5 feet) Features and Usage Build Quality: These lenses are known for their robust, all-metal construction, offering smooth focus operation. Image Quality: It is considered a reliable, high-quality standard lens that provides good sharpness, especially when stopped down slightly from its maximum aperture. Compatibility: While designed for Minolta MD and earlier MC mount film cameras, the lens can be adapted for use with various modern mirrorless digital cameras using an appropriate adapter.