Nikonos lenses are the only lenses that have been designed specifically for underwater use. The lenses for the Nikonos RS in particular have attracted a great deal of attention and are regarded by many as being amongst the best optics made for underwater use.

At the recent ADEX show in Singapore, Seacam owner Harald Hordosch showed me his new conversion for the R-UW AF Fisheye-Nikkor 13mm f2.8 lens. He completely strips the Nikonos lens apart, re-houses it and then uses the glass dome and bezel from the original lens as a port for the lens.

There are well known issues with the electronic compatibility between RS lenses and “modern” Nikon SLRs and Harald recounted how he approached Nikon to try and get up to date circuitry from them. Apparently when they discovered why he wanted then circuits, they declined to supply them, which forced him to re program and modify the existing RS boards.

Borut Furlan has shot the following test shots with a D800 using the lens:

It will focus pretty close too:

The results above show that the lens has very acceptable corner performance even at f2.8. It’s small form factor, f2.8 aperture and great corner performance may make this an ideal lens for bigger animals in the blue, and close-focus wide-angle.

Harald has quoted a price of 1580 euro for the conversion work. Of course, this assumes that the one already owns an RS 13mm. He is ready to perform the conversion now.