EXAKTA (Cosina) 24mm f/2.8 Macro P-KA lens
I believe I have the original (same lens) Cosina 24mm f/2.8 macro but in a Nikon F mount. I read somewhere this lens was one of the last manual 24mm Cosina made, and have a very special lens coating providing very good pictures. I took several film pictures with this lens and like it a lot. Your pictures are great. I purchased a F mount to micro 4/3 and intend to use this lens in my new GH2. At 50mm (double) it should be very good indeed.