Auto Helicoid AR
The Auto Helicoid AR is mounted between lens and camera body to widen the distance. It works like a length-adjustable extension ring. The additional distance caused by the Auto Helicoid AR can be adjusted by a turning ring in the range from approx. 47.5 mm (approx. 17/8") up to 69.5 mm (approx. 23/4"). The additional extension can be read in millimeters from a scale on the Auto Helicoid AR.
The Auto Helicoid AR does not contain any optical elements, it just enlarges the distance.
Aperture functions and widest aperture of mounted lens are transmitted to and from the camera body by the Auto Helicoid AR – different from the original Konica extension rings or the Konica bellows. Mounted lenses can hence be used normally with AE mode. To use AE exposure, the aperture ring of the mounted lens needs to be set to EE or AE, respectively. The selection lever on the Auto Helicoid AR needs to be set to A. Manual aperture setting on the lens is also possible; in this case, the lever on the helicoid needs to be set to M.
The Auto Helicoid AR is mainly designed for use with the Konica Macro-Hexanon AR 105 mm / F4, but in principle it can be used with any Konica AR bayonet lens.
The Macro-Hexanon AR 105mm / F4 is a so-called bellows head. It is intended for macro use on bellows or on extension rings and has no helicoid for focusing. The focusing is normally done by the bellows extension. The lens does not have the standard flange-film distance of the other Konica SLR lenses (40.5 mm) – would you mount this macro lens directly on a camera body, it would be far too close to the film plane to be able to make a sharp image.
With the Auto Helicoid AR, the Macro-Hexanon AR 105 mm / F4 can be used on a camera body without bellows, and it can be focused the normal way by turning the helicoid's ring. At the minimum length of the Auto Helicoid AR, you get infinity focus with this macro lens. If you set the Auto Helicoid AR to it's maximum length, you can get macro images with a scale of 0.23x (1:4.35) with the Macro-Hexanon AR 105 mm / F4.
With other Konica AR lenses having the standard flange-film distance of 40.5 mm, the Auto Helicoid AR works just like a normal extension ring – you cannot focus on distant objects and can use your lens only for close-distance photography, if the helicoid is mounted.
The Auto Helicoid AR was introduced to the accessory program together with the Macro-Hexanon AR 105 mm / F4 roughly with the introduction of the Autoreflex T3. But it did not stay there as long as the matching macro lens, which was offered until the end of the Konica SLR era in 1987. The Auto Helicoid AR must have been taken off the list at the time of the Autoreflex T4 – it is still mentioned in T4 manuals and leaflets, but it is missing in later publications. The Macro-Hexanon is still mentioned there, but no trace of the helicoid.
Like most lenses and the tele converter, the Auto Helicoid AR was supplied in a matching leather case. It was equipped with a standard rear cap and a bayonet cap for the front.
A sample configuration with Macro-Hexanon AR 105 mm / F4 and Autoreflex T3N:
The Auto Helicoid AR is quite a rare accessory and difficult to get on its own. If you want to use a Macro-Hexanon AR 105 mm / F4 without bellows or extension rings, you should try to get one of these lenses already together with the matching helicoid.