This is the standard lens for the TOPCON RE-200 and RE-300, the last cameras made by Topcon, released in 1977 by Tokyo Kogaku. It's a RE TOPCOR 55mm F1.7 lens with a Topcon mount/EOS-EF mount conversion. The TOPCON RE-300 was a camera exclusively for export, particularly to Europe. Therefore, it was a "Japan-only" model, and there were few opportunities to see it. However, it was surprisingly Topcon's best-selling lens. The Topcon RE series with Exakta mount and the Exakta EDX series, along with sister models like the K-mount TOPCON RM, EDIXA CX5, QUANTARAY, and CARENA KS/KSM, had various OEM variations. These cameras were more highly regarded and popular overseas than in Japan. TOPCOR lenses emphasize resolution (resolving power) and are known for their fine, delicate rendering. This RE TOPCOR 55mm F1.7 also prioritizes resolution, but perhaps because it was primarily sold in Europe, it seems to have a European flavor. If resolution and contrast are balanced at a high level, it results in a sharp lens that allows for excellent textural expression. However, it's difficult to achieve both in lens design, and the emphasis placed on each is the design philosophy of each optical manufacturer. This design philosophy is one of the determining factors in the character and rendering style of old lenses. Also, the flavoring of the lens changes depending on the country or region where it's sold, which is as profound as the world of cooking. This is an interchangeable lens for a single-lens reflex camera with an Exakta mount, but it has been modified with an EF mount. Due to the lens structure, there is a slight under-infinity focus. (The mount is removable, and it comes with a rear lens cap. The camera in the photo is not included.) There are almost no scratches, mold, or dust. It has been cleaned and maintained during the mount adapter production, so there should be no problem with shooting. It's a lens with a warm, rich color. Why not capture Japanese scenery with this European-flavored Topcon? Thank you for your consideration.