Sigma 17-70 with 6" dome

One issue with this lens is that you need to use the 8" dome port for full zoom range.

I much prefer the smaller 6" domes which allow you to get closer to the subject and to the sand. They are also much more manageable on crowded dive boats.

So I tried it with the 6" dome (for the Nikon 18-55mm) and it works very well BUT you can't zoom longer than 50mm where the lens hits the inside of the dome.