Up for this auction is a Bausch & Lomb – Zeiss Unarseries IB 305mm f4.5 SN 772151. The barrel shows some signs of wear. The iris is missing. Glass is ok, no scratch, fungus or separation. There are some tiny dust and some bubbles which is usual at that time. There is one small dent on the front lens ring. The rear thread is approx 75mm (3 in) diameter. It also has original flange which appox 100mm (4 in) diameter.See on ground glass, it produces a sharp image. But I’ve never used it like that. This lens is very interesting. Unscrew front glass, it became a lens with only rear glass which has a very strong soft focus effect. As my calculate it’s approx 290mm f5. Iris is not a problem because you will use it as a portrait lens. Last two pictures are images taken with it. It will be perfect for your 5x7 or 4x5. I put it on without reserve . I will ship worldwide for $39. Import duties, taxes, and charges are not included in the item price or shipping cost. These charges are the buyer's responsibility. Thank you and good luck bidding.