INTRODUCTION
Nikon’s D700 is a classic pocket-battleship DSLR. It bristles with the heavy weight features of the top of line D3, sharing the same 12 MP FX sensor, image processing engine with 14-bit AD converter and Multi-Cam 3500FX auto-focus system, but in a smaller, cheaper and lighter body. Those last three points are sure to make it more attractive than its big brother to the underwater photographer.

This camera looks set to become very popular with Nikonians keen to get into full frame digital underwater. And having tried it I am certain that nobody who buys this camera will regret choosing it for an instant. But that does not necessarily mean it is the best choice for underwater photography in the Nikon range.

Arguably the biggest challenge to the D700’s potential for undersea dominance is it’s little brother, the D300 armed with its own 12 MP sensor, this time in the DX format. The D300 is cheaper still, has better auto-focus frame coverage, 100% viewfinder and offers a more suitable range of lenses for underwater use.

Given the strengths of the D300, deciding between it and the D700 comes down to the relative merits of DX versus FX, which I covered in my lengthy D3 review so I will try not to repeat myself too much here.

At the time of writing, Nikon’s SLR camera range is capped at 12MP, meaning that the DX versus FX comparisons currently do not consider one potential advantage of a larger sensor - that of increased resolution without noise or diffraction limitations. That could all change in the next few weeks. While these hypothetical new Nikon cameras are still be a few months away from the high street, all indications are that these future FX models will fit in existing housings and could be ready for underwater photography even before housings are available for the Canon 5D Mk2. Obviously for the sake of this review I plan to only consider the D700 in relation to existing Nikon DSLRs, but if you are considering a new Nikon purchase you should bear in mind future compatibility options your housing may allow.

The housing I used for this test was the Subal ND700. This was the actual show-housing that Subal took to DEMA, and I am pleased to reveal that it worked faultlessly in the ocean a few days later. The housing now belongs to UWP Magazine Editor, Peter Rowlands. I am extremely grateful to him for entrusting me with both his brand new camera and housing, allowing me to take it to the Egypt for this review, even before he had the chance to try it.

Unlike the D3 review, which I conducted in three different countries, I completed this review during my annual Red Sea Photo Workshop. This year it took place on MV Blue Horizon, exploring the Southern Egyptian waters between Elphinstone and St Johns. The trip provided a variety of diving environments ranging from pretty shallow reefs, atmospheric caverns, wrecks and, with a bit of luck, encounters with oceanic whitetip sharks. For comparison there were lots of D300s on board (that camera is so hot right now!) in Subal, Sea & Sea, Sealux, Aquatica, Ikelite and Hugyfot housings, plus a wide variety of other DSLRs.

THE HOUSING
I am a long-time Subal user and because of their consistent design philosophy I find any new addition to their range fits automatically into my hands. Diving with the ND700 required no adaptation. Subal’s ergonomic placement of controls means that every important function falls easily to fingers. Push buttons have just the right resistance and command dials require just the correct rotation to change aperture and shutter speed settings. Subal housings are hard to criticise.

Compared with other manufacturer’s I see Subal’s design evolving more slowly with each generation of housing. Fans would argue that there is no need to fix what is not broken, pointing out that increasingly more and more of Subal’s design solutions (such as for gearing for command dials, camera trays and latches) are emulated on other housing brands.

My only criticism of the housing was that the zoom gear did not seem to be correctly aligned with the gear on my 17-35mm. It worked OK, but seemed to be touching the camera. As it was Peter’s housing I decided to leave it alone rather than fiddle with it. I suspect the problem was the position of the gear on my lens as it worked perfectly at DEMA.

Since the ND300, Subals have been available in two different port opening sizes. At present the only lens that requires the wider port opening is the 14-24mm. Peter Rowlands, like me, is far from convinced about the potential of this lens underwater and has stuck with the older narrower port size. The 14-24mm is phenomenal on land, but underwater, behind a dome and unable to take a dioptre, it can be expected to struggle with corner sharpness meaning its potential will be hard to realise. That said, if you are new to Subal, with no money tied up in existing “port holes” it makes sense to go for the wider Mk4 ports. In the future, lenses will surely get fatter not thinner. Adaptors are available to convert between the two port sizes.

The ND700 is much smaller than the ND3, being about equal in size to the ND300. This has advantages for travel and for getting down to eye level for creatures on the sand, but disadvantages for buoyancy. The ND700 is noticeably negative in the water, even without strobes and strobe arms connected. With my heavy Subtronic Alphas attached it became arm-achingly weighty. Neil Rosewarn kindly lent me some spare STiX buoyancy pieces with him, which I slotted over my UltraLight arms.  I was using Subal 45 degree viewfinder (WS-45) for the first time on this trip, but I found that having a neutral rig was essential to get comfortable handling with this eyepiece.

One ergonomic advantage of the ND700 over the ND3 is the placement on the ISO, WB and QUAL buttons on the top, which of course is dictated by their position on the different cameras. On the ND3 (and ND2) they are on the back of the housing, which means that you must take your hand off one of the handles to push them. On the ND700 they are on the top of the housing on the left, within easy reach of your thumb, while still holding the handle (and keeping your eye on the viewfinder). With a camera with such ISO flexibility, this is a particularly useful.

The most challenging button for housing manufacturers on the D700 (as well as quite a few Nikons) is the flash control on the left side of the pentaprism. Quite a few housings fail to provide access to this important control, which allows you to select different flash modes, such as rear curtain synch, and to add exposure calibration for TTL flash. Subal’s neat solution is a lever on the left side of the top of the housing in front of the push buttons (see above).

WS-45 VIEWFINDER
Subal’s 45 degree viewfinder, WS-45, is based on Inon’s 45 degree viewfinder, but with a much more attractive finish and an optimised fit for Subal housings. The finish is also much higher quality than Subal’s GS viewfinder. The viewfinder is more expensive than the popular Inon viewfinder, but cheaper than others on the market such as the Seacam S45. One Seacam user on board, who shoots exclusively with the S45, commented that the Subal finder was “very nice indeed”.

The WS-45 was a new experience for me and unconvinced whether or not we would get along I brought a GS (enlarging, straight through) viewfinder with me too. As it turned out, I fully adapted to the WS-45 after about two diving days and was not tempted to replace it. I am not sure whether Subal recommends that users take their viewfinders on and off themselves, but it is very easy and I will always taken mine off for travel.

The viewfinder can be rotated through 180 degrees with bump stops every 90 degrees. It gives an excellent view of the whole image and also all the shooting data in the viewfinder. Compared with a straight viewfinder there are definitely positives and negatives, but I would stress that whichever you choose you will quickly adapt to its idiosyncrasies.

I found that the 45 degree angle caused me to slow down and to be more thoughtful in my compositions. The angle of view was excellent for shooting vertical and horizontal wide angle, and also for macro shots of creatures on the sand. This would be a great viewfinder in places such as Lembeh. I also suspect that this viewfinder will be particularly advantageous when diving in a drysuit, where your neck movements are restricted.

Compared with a straight viewfinder it makes switching between horizontal and vertical framing slower (because both the camera and then the viewfinder need to be rotated), which caused me to miss shots when subjects changed rapidly, such as a fish school morphing its shape. The other downside was in macro shooting with longer lenses, when photographing at high magnifications and/or with rapidly moving subjects. These subjects are definitely harder to initially locate with the viewfinder, as the angled view is always going to be less intuitive. Although once you have got them in the frame they are no more difficult to follow with the 45 degree finder.

Overall, the positives out weight the negatives and it got me shots that would have been tough without it. Whether the WS-45 is the viewfinder for you will depend on what you like to shoot, but once you have adapted to it I cannot imagine many people will regret the purchase.

MACRO & CLOSE UPS
Our itinerary, which I had decided for the benefit of the workshop rather than my review, was focused on wide angle. However, on most days we only dived one site, leaving the boat moored up while we operated a pool-is-open policy between meal times. Most of us racked up close to five hours in the water, so there was plenty of time for searching out macro subjects even if the sites weren’t exactly the best for it.

I shot the Nikon 60mm (AFD), Nikon 105mm (AFD) and Sigma 150mm (the first two kindly lent to me by Jarret Brown and Andy Barker, respectively). Most of the subjects were reef fish and the 105mm and the 150mm, in particular were the most useful. I discuss the relative merits of these three lenses for an FX camera in detail in the D3 review.

The D700’s auto-focus is fast and accurate, although the frame coverage of the sensors is lacking compared with Nikon’s DX cameras, such as the D300 and D2X (again see the D3 review for a graphic of this). But I should comment that the AF coverage of the D700 compares favourably to Canon’s full-frame cameras. The D700 (and D300) auto-focus was also clearly more capable than that of the Canon 5D’s that we had on board. 5D shooter, Fergus Kennedy, fresh from collecting his award in the BBC Wildlife Photographer of the Year 2008, commented that he was not able to nail fast moving reef fish head on with the ease of the Nikon D300 shooters. The D700 shares its AF CPU with the D3, making it slightly faster than the D300, particularly in the processing heavy Auto-Area mode. For wide angle, of course, all cameras showed exemplary focusing in the conditions.

In my D3 review I commented that the inherently shallower depth of field of the FX sensor made accurate focus more critical. Pity I did not heed my own words as I found I had to bin quite a few shots of fast moving macro subjects, such as anemonefish, because the depth of field was not there to save the day as it does with DX cameras. The less forgiving nature of FX depth of field was particularly noticeable on this trip because a favourite subject is reef fish, shot in balanced light against the rich blue water of the Red Sea. To get this look it means shooting at around F8-F13 (at 1/60th-1/125th), which does not provide limitless depth of field.

That said, I did continue to shoot some open aperture shots, making use of the shallower depth of field of the FX system, to isolate subjects against pleasing bokeh backgrounds. All in all the D700 was a fine camera for macro.

WIDE ANGLE
The Red Sea is an excellent wide angle destination, with vibrant reefs, caves, pinnacles, walls, wrecks, schools and if you are lucky encounters with pelagics. And all this in clear waters, with not a cloud in the sky to quench the sunshine.

Most subjects here, lend themselves to fisheye photography and having dismissed the Nikon 16mm as less desirably to the more modern Sigma 15mm in my D3 review, I decided to put my views to the test by taking the Nikkor to the Red Sea. In reality, under most shooting situations, there is little to chose between them. Both are sharp and work very well behind Subal’s FE2 dome. I feel that the Nikon resists internal dome reflections better, while the Sigma is marginally sharper a focuses noticeably closer. On one occasion when I was shooting an attractive red anemone with the 16mm + teleconverter, I was frustrated to run against the minimum focus. I was pleased with those shots, nonetheless, but felt there was a possibility for something different if I had been able to get closer still. I was already very close.

As has been widely discussed on the Wetpixel forums perhaps the biggest loss of FX over DX is the inability to use the Tokina 10-17mm fisheye zoom, or to have a real alternative to this lens. This lens offers such a perfect range for underwater wide angle photography, that it is the most compelling reason that many have found to stick to DX. The Tokina 10-17mm on DX covers 180˚ to 100˚ corner to corner. Compare this to the 14-24mm and 17-35mm on FX, which give 114˚ and 104˚ at their widest, respectively, and you see that there is relatively little overlap in their angles of view. Furthermore, the FX options are both rectilinear lenses, which are harder to optimise behind domes.

On the D700 the Nikon 16mm or Sigma 15mm both match the Tokina’s coverage at the 10mm end on DX, and exceed its sharpness and lessen its tendencies chromatic aberration. 180 degree coverage is ideal for most reef wide angle in the Red Sea and for scenic work I did not miss the Tokina. But a prime fisheye can be a bit too wide for marine life. The Tokina can be zoomed in, the FX fisheyes cannot. I did use the Nikon 16mm mounted on a 1.5x teleconverter simply to reduce its coverage to about 100 degrees for certain subjects. This decision had to be made before a dive, but it gave me a wide angle option with excellent corner sharpness and only mild barrel distortion.

RECTILINEAR CORNER SHARPNESS
The Red Sea trip also gave me the chance to shoot the rectilinear 17-35mm in some more detailed field tests. As I elaborated in my D3 review, one of the potential downsides of FX is the blurred corners of wide rectilinear lenses, which have the potential to be more prevalent on the larger format.

With the D3 I was satisfied with the corner sharpness with this lens when shooting the great white sharks in Guadalupe. But I would be the first to admit that images with blue ocean in the corners is hardly a challenging test. Red Sea reefs would be a tougher proposition with plenty of detail that needed to be retained in the corners. I used the 17-35mm with a +4 dioptre behind a Subal FE2 dome and a port extension ring and shot several scenes at a range of apertures using the widest end of the zoom (17mm).

Crops (50%) from bottom left corner:

The corner sharpness results from the 17-35mm are better than I had expected. I shot subjects that I thought would highlight corner sharpness problems. I using the lens at the widest zoom setting, choosing subject matter close to the camera and lighting the entire frame, to reveal detail in the corner of the frame. I find these results completely useable at apertures of F8 and above and they even stand up well to a pixel peeping examination. As I found in my D3 review, this lens (or at least my port setup for it) is prone to chromatic aberrations on areas of high contrast (in this case tips of the fire coral). When I get a FX camera of my own I intend to experiment with my port setup and would expect to improve this performance further.

I also had another chance to experiment using the auto focus fine-tine feature to apply a focus offset, closer to the camera, for the 17-35mm in an attempt to improve corner sharpness. Frustratingly, the results were inconclusive really because the corner sharpness was so decent in the first place. In the end I could not tell any difference between the before images and the after ones, which suggests that first the effect is not very large and second I need some more controlled conditions to observe it. I’ll try and get the 17-35mm and a D700 or D3 in the pool soon.

SUNBURSTS & OTHER HIGHLIGHTS
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.

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.

HIGH ISO
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.

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.

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.

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.

WIDE ANGLE SUMMARY
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.

COMPARISONS
It is hard to see many favouring the D3 over the D700. The D700 packs the same imaging system (sensor & processing) into a smaller, lighter, significantly cheaper body. As a result the housing is smaller too, although this means it is more negative in the water. Additional buoyancy is recommended.

The only significant area that the D700 falls short of the D3 for underwater photography is the viewfinder. On the D3 (and D300) it gives 100% coverage, on the D700 it shows 95% in each direction. I liked the D700 so much I would love to tell you can’t see this difference. But you can. Particularly when shooting a fisheye, these last few percent represent quite a few degrees more of coverage. With a viewfinder as nice as the WS-45, which gives such a perfect view of the corners of the frame, I found it annoying to discover that these weren’t the actual corners. This is far from a deal breaker, but it is important to be aware of it.

The D300 makes stronger case against the D700. There are some who will buy the D700 because they must have a “correct” sized sensor. This is misguided reasoning, particular because DX offers a better range of lenses for underwater photography. The D300 offers better AF coverage and 100% viewfinder against the D700’s better higher ISO performance and slighter sharper AF responses. The D300 is much cheaper too, although in system costs the difference is not that large (D300 and D700 housings will cost about the same).

Decisions are further complicated when we speculate on vapourware. The next arrival seems likely to be a D3X, which if reports are to be believed will slot straight into D3 housings by early 2009. Tests with the 24MP Sony α900 show that these sensors will significantly out resolve the 12MP cameras. But whether you need that resolution is a debate for another time. Nikon released the D700 just 3 months after the D3, and it seems reasonable to expect a D700X could appear at either the same time as the D3X or soon after.

Another intriguing possibility is fitting a D300 in D700 housing with a different back (to accommodate the different position of the viewfinder). The D700 is taller than the D300, so won’t fit in many D300 housings. But housing manufacturers could offer an alternate back for the D700 housing to take the D300. This would allow the photographer to travel with a spare camera, and a French Subal dealer Michael Warren pointed out to me at Antibes, also give each lens you carry two effective focal lengths doubling your options. We shall see if any manufacturers are attracted by this idea.

CONCLUSION
The D700 is a highly capable camera for underwater photography, offering the same imaging system as the D3 at a cheaper price and in a smaller package. If you want to shoot FX underwater it is the obvious choice. It is bound to be a very popular choice for Nikon users. The Subal housing is an excellent complement to the D700, and kudos to the Austrians for getting this housing to the market so quickly.

Both the D700 and D300 are excellent underwater cameras. If pushed I would conclude that the D300 offers the marginally better system (e.g. 100% viewfinder, Tokina 10-17mm, better AF coverage), irrespective of price, unless you have a bona fide need for high ISO. However, if despite this you choose to go with D700 you would not regret it for a heartbeat.

When I shot the D3 I was full of admiration and respect for its abilities, with the D700 I loved them. There is something intangibly correct about the balance of features of this camera. Throughout the trip I kept referring to it as a sweet camera. I also really valued travelling with a small housing again. I am incredibly tempted to go out and buy one. I can argue why the D300 is probably a marginally better system, but I just want to use the D700 more.

Alexander Mustard (www.amustard.com). 17th November 2008.

Acknowledgments
Thank you to Peter Rowlands for lending me his Nikon D700 and Subal ND700 for this review. Thanks also to all on board Blue Horizon, especially Neil, Jarret, Andy for lending me kit to improve the scope of this review.
I hope to be testing some other D700 housings in the next few months. I look forward to reporting my findings here.