Parts 

8" of 1 1/2" PVC pipe, a 1 1/2" Cap, a 1 1/2" Union, and a 2 7/8" LEXAN disc.

Glue the half of the Union with the O ring on one end the 8" pipe and Cap on the other 

Now to make LEXAN lens use a drill press with 3 1/8" hole saw (WITHOUT centering drill bit). Have some choices here you can use 3/32? LEXAN from home store (window pane replacement area) or order something thicker on line. I've tested the window pane replacement down to 510' but I'm trying to get to 700'+ so I ordered some 3/8". 

If you're using thinner stuff you'll need to use the other half of union fitting to make it thick enough. You'll need to trim the fitting so it doesn't get in camera view.

Or with 3/8" LEXAN

IMPORTANT make sure it's polycarbonate (LEXAN) haven't tested plexiglass but it breaks easy so if you do test first and leave a comment on how it did.

I'm hacking a 'power bank' from target ($10) to power the Pi Zero and Pi Camera

Ripped out of case and added another battery.

This will run my Pi for 12+ hours. Note can only have one thickness of tape and still fit in PVC case and the strip of tape (folded back on itself so not sticky) is to make it easier to pull out of the case.