■ Digital photography

A great number of Konica users have been trying to figure out how to use their Hexanon glass on a digital medium. To get at the essence of the problem, it is important to understand the concept of film-to-flange distance, also referred to as back register: Optically speaking, the lenses of all SLR systems are designed in function at a specific distance from the film plane. This distance is the maximum distance from the film plane at which the lens may be mounted in order to allow infinity focus (∞). The prospect of mounting Hexanon lenses on other cameras, digital or otherwise, gets pretty hopeless when one realizes that the film-to-flange distance of the Konica AR mount is one of the shortest in the SLR industry (40.5mm). The choice of such a short film-to-flange distance was most probably due to Konica’s comparatively modest range of lenses in the middle sixties, and its desire to make it possible to mount lenses of other makers on Konica bodies, using an adapter providing the requisite film-to-flange distance.

Most regrettably, this choice had the additional consequence of making Hexanon lenses unusable on most other mounts. On any other camera, Hexanon lenses find themselves at a distance from the film plane that is greater than the 40.5mm of the Konica’s AR mount (Canon FL/FD – 42.00, Minolta – MC/MD 43.50, M42 – 45.46, Olympus OM – 46.00 et Nikon NK – 46.50), thus making infinity focus impossible. In general, on any body other than Konica, Hexanon lenses can only be used for macro photography (with admirable results – see here).

It would seem, thought, that there is a small light at the end of the tunnel (and it is not that of an oncoming high-speed train...). A number of digital SLRs have a mount, called Four-Thirds (4/3), whose film to flange distance, only 38.58mm, is shorter than Konica’s AR mount. This standard, initially designed by Olympus, was later adopted by other makers, such as Panasonic (Lumix) and Leica (Digilux). The difference between 38.58mm and 40.5mm is a measly 1.92mm, which is insufficient for an adaptor ring. It is so short in fact, that the Hexanon lens' aperture actuating cam gets in the way and needs to be removed. For a perfectly reversible operation, it need to be unscrewed, but some irreverent tinkerers simply saw it off. The lugs on the two mounts are so similar otherwise that getting the Hexanon lens to sit snuggly on the 4/3 camera is a matter of shimming it properly.

A number of intrepid experimenters have shown how to do it on the web. Their technologies range from in-house tinkering to highly professional machining:

1. Morten Øen explains what to do here, and shows the results here;

2. Jörgen Bergfors shows his conversion of Hexanon lenses here and here.

3. Henrik Lewander has a blog on which he goes over the necessary modifications and shows pictures taken at different apertures;

While on the subject of adapting Hexanon lenses for use on a 4/3 body, it is important to remember that the dimensions of the sensor on a 4/3 body are half that of a 35mm frame (24 x 36mm). This has two consequences: For one, every defect on the captured image (undesired detail, dust, etc.) will be twice as large as in the case of an image captured on a 35mm negative and that the effective resolution of any lens designed to be used on a 35mm body will be reduced by half on a 17 x 24mm sensor and two, the captured image will have been produced by the central portions of the lens which, as we know, are the best performing parts of any lens. 

One should thus not expect the performance of Hexanon lenses on a 4/3 medium to be as outstanding as on a Konica body. Naturally, the most satisfactory results will be obtained using the best Hexanon lenses. Among the latter, one should mention the 40mm f1.8, the 50mm f1.7, and the 85mm f1.8 (a equivalent focal distance of 170mm at f1.8!). This said, I think that given the quality of the entire Hexanon range of lenses, results should be quite respectable.

Update 

In August 2007, Panasonic introduced the Lumix G1, a small micro 4/3 digital camera with interchangeable lenses based on a reduced 4/3 format. In this format, the sensor remained the same, but the mount was made smaller, allowing for the use of much smaller lenses for a given focal distance and a much smaller body. What made this possible is the removal of the entire optical viewfinder and the mirror box. This was the world's first 'mirrorless SLR' (supposing the use of the term 'SLR' in reference to a camera without a mirror makes sense at all). The camera is equipped with an electronic viewfinder (EVF) and with a live preview function on the viewing screen. All this has made it possible to reduce the flange to sensor distance to a mere 20mm. Adapters enabling the use of Hexanon lenses on the G1 have been on sale since the middle of 2009. In time, Olympus, Sony and Samsung also introduced their own mirrorless, interchangeable-lens cameras (the Pen series, the NEX series and the NX series respectively). In contrast to the micro 4/3 Panasonic and Olympus cameras, which are based on a sensor that is half the size of a standard 35mm frame (a crop factor of 2), the Sony and Samsung mirrorless cameras are based on an APS-C type sensor (crop factor of 1.5). Watch the price of Hexanons increase as the number of their potential applications multiply.

●  KONICA  ●