Nikonos RS 13mm to Sony Conversion I have developed a procedure for converting the legendary Nikonos RS 13mm (the sharpest underwater wide angle lens) to modern Sony E mount by removing the optical elements from a Sony 50mm f/1.8 donor lens and replacing them with those from the 13mm. After the conversion the lens has native Sony autofocus and aperture but with the optics of the 13mm. It is also possible to use the converted lens on Nikon Z cameras with the Megadap Sony E to Nikon Z adapter. For the port I separate the 13mm dome from the rest of the lens and install it on a port I 3D print out of PETG plastic. I pressure test the port to 100m/330ft. I am currently producing ports for Nauticam N100 Sony mirrorless and Isotta Sony mirrorless. I will be adding Nauticam N120 Nikon Z, Seacam Sony mirrorless, and others in the near future. The converted lens has a larger maximum aperture of f/1.8 compared to f/2.8 of the stock lens. It can also focus both closer (basically to the dome) and farther than the stock lens. Additionally, I have developed an optional CRC (close range correction) system that significantly improves edge sharpness at close distances over the stock lens, but for those who do not want to deal with the added complexity there is the option to leave it off. The conversion fee is $1000 USD (or $750 if you only want me to convert the inner lens and have the port made elsewhere). Adding the CRC system is $100 extra. There is also the cost of the Sony 50mm 1.8 donor lens (~$200), which I am happy to source if the customer wants. I also ask that the customer cover the cost of return shipping as well customs fees if I happen to be charged any (usually I am not). I am located in Harrison, Arkansas, USA. Feel free to send me an email if you have any questions or are interested in ordering a conversion.