What extension for 100mm Macro lens, Nauticam?

[Entacmaea]

Hi there, I have a Canon t4i in a nauticam housing, and am trying to plan ahead for doing some other super macro and WAM stuff. I currently have a 4" zen dome and tokina 10-17, and a macro port 41 and 60mm lens for macro. Does anyone know what extension I will need to add to the macro port 41 to use a 100mm behind it? I'm hoping I can use the same extension for that, and to add a Kenko teleconverter down the line to my dome/Tokina- but that may be wishful thinking.

Thanks!

Best, Peter

 

[OceanEyes]

Hey Peter.
I'm not familiar with the 41 port, but the basic extension that you'd need for the Canon EF 100mm f/2.8 macro lens is aprox. 46mm more than required for your current lens. You might try contacting the folks at Reef Photo in Ft. Lauderdale, (the guys who produced your Zen dome port.) They are a big Nauticam dealer and should be able to get you exactly what you need. I've been doing business with them for several years and have only good things to say about the outfit. Out your way, Backscatter in Monterey is also a reputable Nauticam dealer.

There is a slight chance that you could use the same extension ring for your dome/Tokina/Kenko, but I would not bet on it. The nodal point of any lens or lens/tele-converter/extension tube combination MUST be ideally located in relation to the interior curvature of a dome port in order to produce sharp images. Each lens or lens/tele-converter/extension tube combination may well require a different distance between the lens mount and the dome port, and thus a different extension ring or combination of rings.

 

[DelrayDM]

Which 100mm lens? It will make a difference.

Canon EF 100mm f/2.8 Macro USM

or

Canon EF 100mm f/2.8L Macro IS USM

I'll get the answer for you.

 

[OceanEyes]

DelrayDM is correct. The IS lens requires an additional 7mm of extension.