I use autofocus for almost every underwater photograph I take and I value AF performance above many other factors when selecting a camera. On this shoot, I used a Fisheye FIX Light on all but one dive while in the dark waters of Port Hardy and San Diego and perhaps unsurprisingly the D3’s autofocus proved fantastic. It quickly and accurately locked onto just about every subject I wished to photograph. However, the wide, soft illumination from Fisheye Fix Light is so good that even poor AF will be flattered. So I made one dive in San Diego without the light and took the camera down to 20m (85ft) in viz of less than 5m (15ft) with no illumination and still found the AF very capable for macro. Nobody else on the boat considered shooting macro without a focus aid in these conditions, but the D3 could. In Guadalupe, photographing large subjects close to the surface it was unsurprisingly faultless.
Before trying the D3 underwater I had two concerns about the D3’s AF system. First I was frustrated that Nikon had decided to do away with the 5-point grouped AF that I use about 80% of the time on the D2X and second, I felt the poor frame coverage of the D3’s 51 point Multi-Cam 3500 AF module was limiting. I would happily have less points and more frame coverage.
To my pleasant surprise, the lack of a grouped AF mode was not a big deal. Unlike the D2X where I can generally stick to Grouped AF so much of the time, I found that the D3 worked best switching between the three AF Area modes for different scenarios, but once I got used to this I was very impressed. Jumping ahead to wide angle I found that Auto-Area AF worked very well on every subject I shot. Perhaps, only when shooting strongly backlit (into the sun) compositions might you need to switch to Single-Area AF. I also found that Auto-Area AF worked very well for many macro subjects too. The D3 has a rare ability to pick a subject out of the background and focus on it, with red squares blinking on the viewfinder to confirm the exact point of focus.
When shooting macro with an FX camera, the depth of field will be less than with a DX camera with the same framing at the same aperture and therefore it is important. Shooting FX is a reminder that DX shooting can develop some bad habits particularly sloppy “near enough is good enough” focusing. For this reason I would also use Single-Area AF when wanting to be very certain of focus. Port Hardy is an amazing dive destination with vertical rock walls plastered with super colourful sessile invertebrates (sponges, anemones, barnacles and soft corals). Hiding within this multicoloured jungle are lots of photogenic critters (nudis, crabs and characterful fish, such as sculpins and warbonnets). From a photographic perspective one of the biggest challenges is getting good subject isolation. We would all spend a lot of time searching for angles that would allow us to place subjects against open water. None of us believe in picking up and moving subjects for the sake of a shot. One appealing aspect of FX was the naturally shallower depth of field and I shot a large number of narrow depth of field or bokeh shots as Martin Edge classifies them, to include the colour of the background, but not the distracting details. I found the Sigma 150mm particularly affective, when opened up to F4.5-F6.3.