Adapter on lens or tube?

[smahn]

I want to mount a Nikon lens onto an EOS body with an extension tube. The tube has not yet been bought. Should I get a Nikon ext tube, mount the lens to it, and put the lens adapter between the tube and the camera? Or get a Canon tube and put the adapter between the tube and the lens?

Where best for the adapter, and in what sequence should items be attached?

[elf]

I want to mount a Nikon lens onto an EOS body with an extension tube. The tube has not yet been bought. Should I get a Nikon ext tube, mount the lens to it, and put the lens adapter between the tube and the camera? Or get a Canon tube and put the adapter between the tube and the lens?

Yes.  

Where best for the adapter, and in what sequence should items be attached?

Adaptor manufacturer will provide instructions.