A friend recommended a Nikon 70-180mm macro lens. Nauticam doesn't make a zoom gear for this lens and it's kind of tricky to fit. I broke out the CAD software I use for underwater inspection reports and got up to speed with developing 3D parts for 3D printing. There are a few changes that I'd make, but it works really well. It's nice not to be limited to most common lens choices. Has anyone else experimented with 3D printing accessories?