Kühn Flexameter: A 94-Year-Old Forgotten Photographic Accessory

The Kühn Flexameter, a waist-level viewfinder accessory designed for early Leica cameras, is highlighted in a new video by photographer Mathieu Stern. Invented 94 years ago, the Flexameter features a focusable lens that provides 1:1 focusing information, allowing photographers to manually transfer distance values to the camera's taking lens. It was created by Kühn, a company founded by Kurt Kühn and Elsie Leitz-Kühn, daughter of Ernst Leitz II. Elsie played a key role in its development. The device was a short-lived solution for precise focusing before Leica introduced coupled rangefinders in 1932. Stern's video demonstrates the Flexameter's functionality using a custom camera setup. Though obsolete today, it remains a rare piece of photographic history.