The Mamiya RZ67 37mm f/4.5 Fisheye is an ultra-wide fisheye lens for the 6x7 medium-format RZ67 SLR system, produced under the Sekor Z line. It is one of the widest options available in the RZ67 mount and was designed to deliver a hemispherical field of view on the large 6x7 frame, primarily for architectural, landscape and creative work where extreme distortion is wanted rather than corrected.

Sales data is thin: a single recorded UK auction hammer result of £420 in April 2024 is the only data point in our records, so it sets both the median and the only known price marker rather than a true range. Because this is a low-production specialist optic, hammer prices for clean copies in the auction market can move sharply with condition and completeness of accessories, and as of 2026 buyers should treat the £420 figure as indicative of wholesale saleroom level rather than a retail value or what a dealer would ask. Clean glass with original caps and rear filter holders typically commands a premium over user-grade examples when they appear at auction.