I recently did multiple shark dives in Yap with my new d500 in a Nauticam housing.Being a previous full frame shooter I used my nikkor 16-35mm lens along with the Nauticam 8.5" dome and the 70mm ext. ring recommended in the Nauticam port chart.All of my images were soft-even some taken of a stationary moray eel on site.I tested the lens/port/ext. ring combo on land and the resulting images were sharp.I subsequently shot the sharks using a 20mm nikkor,and a 60mm nikkor ,and a 15mm sigma fisheye with good results.I discussed this phenomenon with a Nauticam rep.and his suggestion was to try adding another 20mm ext. ring to the combo.Anybody have any similar experiences/suggestions/solutions?
D.K.S