With 65 grams and a 33 by 39 mm size, the TV-Heligon 19mm, or its optical bloc, is a tiny lens, very different from the other fast lenses often seen here. The 1cm working distance is too short for practical use on F mount but on CX or on a Sony Nex it reaches between 5 or 8 cm, depending on the configuration and the lens being mounted straight or reversed.
In its raw form, it looks like picture 1 below. Hopefully, the optical block is in one piece and, unscrewed, reveals a M30 inner thread perfectly suitable to attach all sorts of eBay adapters.
However, the easiest mount is reversed and stuck on a Nikon CF, which is a perfect fit for its outside diameter. 2 rubber bands for security and it’s done. In this configuration, the working distance is 6 cm and puts a 43mm wide field of view on sensor.
