Field Review: Nikon D750 in the Red Sea

With Nauticam NA-D750 housing

By Alex Mustard.

Sensor Performance

The image quality of the Nikon D750 is from the top drawer, there can be zero debate about that. In terms of dynamic range, DxO measure it pipping both the D800 and D810 at ISO 100 and 200 and having a larger advantage above ISO 1000. Lightroom cannot current read the D750 RAW files, so I had to convert them into DNG files in Adobe’s DNG converter, which can read D750 NEFs and then import the DNGs into Lightroom (I mention this in case the process was slightly detrimental to the image quality of the files – I didn’t think it did).

Personally I think that 24 MP is all the resolution most of us ever need (as it happens, my wish for the D5 is 20-24MP with pixel level image quality that at least matches the D4). It is easy to be impressed on screen by the astonishing resolution of the 36MP sensor in the D800 and D810, but unless we have a need for huge reproduction, we have to honestly ask how many of the pictures taken with it really needed to be taking up so much space. If you are a very active underwater photographer, shooting throughout the year, the hard drive demands and slower workflow of 36MP are “half as much again” more significant. Now the launch is a distant memory, there are not many Canon photographers who remain upset that the 5D Mk3 did not increase on the 5D Mk2’s 22MP count.

Compared with the D600 and D610 the 24MP sensor in the D750 is tuned slightly for increased detail over super clean files. Nikon are clearly responding to what their customers want and I find myself slightly out of step. I love the look of the D600 images I have shot and find the slightly more detailed but noisier D750 files marginally less pleasing, especially in the blues and the shadowy caves. But these files are all so detailed that I should remember that most of this noise is only visible on the screen and will be down sampled out when the images are actually used.

As with all of Nikon’s cameras the noise comes in very gradually as the ISO clicks upward and with such high resolutions it then disappears again when the files are downsized. The result is that the main limitation of noise at high ISO is really on final reproduction size. As a result, I would say that there is no 4 figure ISO that is unusable, but the higher the ISO the smaller the image must be reproduced (I stayed below 3200 when not specifically testing ISO).

Overall, I was a bit surprised that the noise from the 24MP FX D750 was not a bit better (despite matching the D810), especially when compared to the year old, 24MP DX D7100 I own (see results here). It is clearly better than the DX camera, but not by as much as many would expect. The DxO results shows it holds only one stop advantage, which is consistent across the ISO range. One stop is an amount that a DX underwater photographer can easily get back on the aperture compared to a FX shooter, while maintaining the same corner sharpness (assuming the same dome and lens angle of view). Ultimately, this says more about how amazing the D7100 is, rather than any paucity in performance in the D750. But it does raise the issue that in real world shooting, FX might not yield any significant advantage over DX for high ISO underwater photography.

Dynamic range and the ability to hold highlights, such as sunbursts remains an area of interest amongst underwater photographers whenever a new camera surfaces from its first few dives. I think performance reached acceptable levels at least eight years ago in pro cameras and a few years later in consumer bodies. Since then there have been improvements, but each is small. When the D800 arrived I took it on one of my Red Sea workshops and shot sunbursts side by side with a D7000. We then showed them to the group of experienced shooters and no clear winner emerged. The D800 should win on paper, but in reality the differences are tough to see.

The D750 continues to push out that “on paper” advantage, just exceeding the standards of the D800 and even D810. So it clearly does a fine job, but it does not mark a big step over previous generations. These days you need to skip one to two generations to see a demonstrable change. If you are buying something new you can be sure it will be better than something old, but if you old camera is only a couple of years old, you will have to look very hard to notice the improvement in dynamic range. The D750 is a leader, but it isn’t epoch making.

In conclusion, the D750’s state of the art sensor simply excels in all departments. Point it at any subject and you are assured you have image quality to match anything anyone else is shooting.

Conclusion

The Nikon D750 is a highly specified, highly capable camera, which is most definitely suited to underwater photography. Its launch price is the same as the D610’s was and we can view it as a next generation upgrade in all aspects. The only people who don’t see/admit this are Nikon’s marketing department (perhaps they still have D610 stock to sell?)! It is a no-brainer over the D610.

In comparison to its big brother, the new D810 (the D800/D800E replacement), it is far more of a tempting prospect than the D600 was compared with the D800. Unlike the cameras these replace, the cheaper option now has marginally better autofocus (and higher frame rate) meaning it is now arguably better at getting the shot than its big brother. The D750 costs considerably less (the price of a quality piece of glass) and matches the D810 in many aspects of image quality, even slightly out performing it in a few areas. The camera is smaller and lighter too, and this means housings are as well. Most housings will be a bit cheaper too.

To drop some D750 negs - the fastest flash synch speed is a 1/3 stop less than the D810, the viewfinder is not as nice, in my opinion, and the built in WiFi is unlikely to be a deal clincher for underwater shooters. Most obviously it lacks 12MP of resolution, but in providing such a strong all-round product, Nikon will really make photographers question how much they really need that extra resolution when choosing between the two. In short, Nikon users are lucky to have such choice.

But these two are not the only choice. The third comparison should be with the DX format D7100, which also has 24MP, and boasts comparable autofocus performance and only marginally inferior image quality in terms of resolution, ISO and dynamic range. All three cameras greatly exceed what almost all of us need, almost all of the time. The only real flaw in the D7100 is that it suffers significant diffraction when lenses are extremely stopped down in super macro shooting. But the D7100 remains the best DX camera Nikon have made to date. Underwater photographers should not make the mistake of thinking FX good, DX bad. If you are considering the D750 you should thoroughly examine the case for the D7100 as well as the D810, reassured that there are only good decisions on the table.

Nauticam’s NA-D750 is a fully featured housing that provides access to all camera controls. The primary controls of shutter, shutter speed and aperture are all excellent. The multi-selector on the back of the housing is the best solution across the industry. There are plentiful levers, which place important controls under your thumbs, although I found the placing of the thumb focus lever difficult to reach. The port lock and housing locks are very easy to use and Nauticam have the best integrated vacuum system on any housing I have tried. Nauticam deserve a great deal of credit for their relentless drive to constantly listen to their photographers and continually improve their designs.

So am I going to get one? Nope. Unlike when I brought the D700 and D7000 to the Red Sea in Novembers past, I am not motivated to rush out and buy. But this says more about me than the camera. The D750 out performs those two cameras in all important areas and Nauticam’s NA-D750 really moves the game on even from the brand new NA-D7000 I used here four years ago.

The bottom line is the blend of talents that endow the Nikon D750 will clearly make it the perfect underwater camera for many. And if I was told to use only this system for all my shooting for the whole of 2015, I would be completely content.

Alex Mustard. November 2014.

Page 1. Introduction.
Page 2. The Nikon D750.
Page 3. The Nauticam NA-D750.
Page 4. Autofocus Performance.
Page 5. Sensor Performance and Conclusions.