Article Summary:

Steve Williams had some time recently and tested his Canon 40D / Sea & Sea underwater housing setup with a 17-40mm lens and various Sea & Sea dome extenders:

In preparing for a JASA wild dolphin trip next week I’ve been trying to determine the best port configuration for my 40D using the 17-40L. The Sea & Sea chart recommends the NX Fisheye dome with no extension. My early simple checks in the pool showed some very soft corners with this setup… I shot a sequence of apertures; 4, 5.6, 8, 11, 16, 22 at 17mm, 29mm, and 40mm for each of four configurations with my NX fisheye dome… The Sea & Sea recommended configuration provided the worst corners in all cases.