Field Review of Nikon D700 in Subal ND700

Since digital cameras have superseded slide film for underwater photography, one factor more than any other has left us hankering for the good old days. Sunbursts. Slide film’s non-linear recording of highlight detail meant that it was naturally predisposed for capturing the sunballs and shafts of light that are so evocative of atmosphere of the underwater world.

Shooting digital we had to adapt our techniques for capturing this light with our digital sensors. Frame and expose carefully and this wonderful submarine light can be recorded effectively in pixels. But for Nikon users the D3, D700 and D300 offer new tech, in the form of the 14-bit Analogue to Digital conversion and therefore 14-bit RAW files that have the potential to expand dynamic range and help in this area.

The D700 does a very decent job with sunrays, but like other digital cameras it is still best to hide the sunball. Nikon D700, Subal ND700.  Nikon 16mm. Magic Filter. 1/200th @ F9. ISO 200.

Without performing rigorous back to back tests it is hard to quantify such a subjective image property as the look of sunrays, so must comments tend to qualitative. Martin Edge, in his review of the D300 here on Wetpixel, concluded that he felt that the D300 outperformed the D2X in this area. I concurred in my D3 review, confirming that the D3 was not a match for film but better than the cameras (D2X, 40D) I was shooting alongside.

The D700 seems equally capable, and perhaps the best commendation I can give it to say that using the D700 in the Red Sea I was never afraid of shooting towards the sun. As you can see from many of the images included in this review. Typically windy, the Red Sea weather meant that we did not get may opportunities to shoot beautiful sunrays, but having shot the D700 in more familiar territory, I feel I can state more strongly that the three 14-bit Nikons are a step on from their predecessors in capturing sunlight underwater. But they still fall short of a sunburst on a transparency viewed on a lightbox (although it should be noted that slides must be scanned and once on the printed page the difference is hard to spot). For the best results on digital it is still advisable to avoid getting the whole ball of the sun in the frame.

A rare wind free moment allows a glassy surface to refract focused sunrays into the ocean. The D700 handles highlight detail better than any pre-14-bit A/D conversion Nikon. Nikon D700, Subal ND700.  Nikon 16mm + 1.5x teleconverter. 1/200th @ F8. ISO 200.

Probably the key strength of the D3/D700 sensor is its phenomenal ability to produce clean images in low light and at high ISO. In Canada, shooting wide angle I certainly got images that I felt would have been impossible with older cameras. But in the clear, blue waters of the Red Sea, more typical of the conditions that most underwater photographs are taken, I was curious to see if this feature was a major capability for underwater photography or simple just a party piece.

The first chance to test this capability came on our first day. The authorities at Port Ghalib had us running late and keen to squeeze a second dive in at Elphinstone we dived right up until sunset. The water was dark, so I turned the D700 up to ISO 800, confident in its ability after testing the D3. The images are clean and incredibly detailed, but shooting attractive wide angle at this time of day is not just about ISO.

Early and late in the day, when the sun strikes the ocean at a more acute angle, the fall off of illumination with depth is much more marked. So, if you expose for a correct blue in the middle of your fisheye frame the surface will be too bright and the depths too dark. In the middle of the day the light penetrates much further, meaning more evenly exposed blues extend down through the water column. At midday expose for a blue in the middle of the frame and you will get an attractive blue from top to bottom.

Reef scenic shot at almost sunset. The high ISO ability of the D700 allowed me to get this shot in near darkness, which as you can see from the 100% crop (right) is clean and detailed at ISO 800. However, the light penetration in the water column falls off much more steeply at this time of day, and I would be better taking this image in the middle of the day, when I would be able to get a blue background throughout the frame and there would be no need for high ISO. Nikon D700, Subal ND700. Nikon 16mm. 2x Subtronic Alphas. 1/20th @ F13. ISO 800.

I guess what I am trying to say is that despite the D700’s high-ISO capability for exposing scenics at this time of day, the ambient conditions do not create such pleasing shots as in the middle of the day. That said, there might be creative reasons for shooting these types of images, or non-scenic types of wide angle where the ISO capability is more use. But if you want to create classic coral reef scenics with attractive blue water backgrounds you are better working in the middle of the day when high ISO is of little advantage.

The next chance to exploit high ISO came when shooting a wreck using available light and the Magic Filter. The Magic Filter usually costs just over a stop of light, and I was hoping that the high ISO abilities of the D700 would be useful here. As it turned out I only had to bump it up to ISO 400 to be able to use the apertures and shutter speeds I wanted. The images are, of course, very clean, but they are not that much better to those shot at ISO 400 on the D300s, 40D or 5Ds on board. All these cameras do a very good job at ISO 400. In darker conditions, a higher ISO might be useful, but filter photography in these typical tropical conditions did not really exploit the abilities of the D700’s FX sensor.

Wreck of a yacht. Even with the filter I did not need to go above ISO 400 to get the shutterspeeds and apertures I wanted. Nikon D700, Subal ND700. Nikon 16mm. Magic filter. 1/100th @ F11. ISO 400.

The best chance to exploit the high ISO capabilities of the ND700 came at St Johns Caves, a wonderful reef cut with a maze of passageways, illuminated with shafts of sunlight from the surface. Not only can in be very dark in the caverns, but the difference in exposure between the focused light beams and the dark cave walls is a real test of a camera’s dynamic range. I felt that this dive site would really show up the advantages of the D700’s 14-bit A/D processor and its high ISO capability.

Finally a use for high ISO! In the dark caverns of St Johns Caves I was able to get images that would have been completely impossible with my D2X. This image is staggeringly clean when viewed at full resolution. Some of what appears to be noise in the frame is actually grains of sand suspended by divers swimming through the caves. Nikon D700, Subal ND700. Nikon 16mm. 1/25th @ F13. ISO 1600.

In the darkest sections of the caves I pushed the ISO up to 1600 and the D700 produced some stunning results. Clean, detailed images that could easily cover a double page spread in a magazine or book.
There is no doubt that Nikon’s 12MP FX sensor is incredibly capable at high ISO, but you have to search pretty hard to find chances to exploit this advantage in normal diving conditions. At ISO 400 many of the other cameras we had on board, like the D300, 40D and 5D, were capable of producing comparable results. Finding justifiable uses for ISO 800 and above is not as easy as it sounds. If the high ISO performance of the D700 is the feature you are most focussed on, make sure that there is a real need for it in your underwater photography.

In summary, the D700 is an excellent camera to use for wide angle photography, handling sunbursts noticeably better than older Nikon digital SLRs. With a fisheye image quality is excellent and I was happy to get completely acceptable results with the 17-35mm over a range of apertures. The high ISO is there if you need it, the focus is excellent at the large LCD screen makes reviewing (or just marvelling at) your images a pleasure.