Using the porthole was easy to attach to my camera lens. In my case I secured the porthole to the manual focusing ring so I could focus by twisting the porthole. The only drawback to this product is ensuring that you do not scratch the acrylic lens.
Build quality is top-notch. Exactly what I was looking for and I'm super stoked to take great close-ups under water of my SPS collection now.
This takes a huge concern off the table of getting your expensive equipment wet. Very study and easy to use