Aquatica Focus Extension Ring for Canon EF 17-40mm f/4
Aquatica is proud to introduce a new and long awaited extension ring especially designed for the Canon EF 17-40mm f/4 zoom lenses. It now sports a knob on its side that connects to the lens focus ring via a gear. This same knob has a retractable mechanism that makes installing and removing the lenses a quick and simple operation.
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This product has been discontinued. Please scroll down for accessories and other options.