Full-frame fisheye + teleconverter + Zen mini-dome combo

I know there has been several posts on the Zen mini-dome already, but most have focussed on the Tokina 10-17 combo.

Being a full-frame shooter I don't have this lens option as such and I'm not keen on the Tokina+ teleconverter option either.

Has anyone in this forum used the Sigma 15mm FE + Kenko 1.4 TC combo behind the Zen DP-100 mini-dome?

1. How is the image quality? (pictures welcome)

2. How much extension you need? - Is the EXR 33mm good enough?

Thanks!

The problem with Sigma 15mm is that to get it to the correct optical position in this dome you need to cut the shade off... With the narrower resulting field of view from the 1.4x teleconverter you might be able to work with a less than optimal (too far forward) dome position, but I haven't tried it.

Extension ring 15 is just right in the current housings with a lens that has had its hood trimmed and the 1.4x TC.