Nikon D800
Busting the Myth of Megapixels

Page 1

(June 2012)

     
 

Page 2 (Noise)
Page 3 (Picture Control, ADL and HDR, Vignetting control, Distortion control)
Page 4 (Diffraction and depth of field, Autofocus, White balance (WB) and monitor)
Page 5 (Nikon D800E, What do I find problematic with the D800?, Conclusion, Post Scriptum)

 
Introduction

As with all my tests of photographic equipment, this test is subjective and non-scientific. Due to a lack of proper lab equipment, which would enable me to carry out reliable scientific measurements, I've tested the photography equipment in comparison to my old equipment (some of it borrowed) under similar conditions. I focused especially on these functions of the new equipment which interest me as an underwater photographer. In other words: I tested this new equipment first of all for my own needs, but decided later to publish the results of my tests publicly. Considering that I had no previous experience with shooting videos, I will not discuss the video quality of the new equipment in this review.

Most of the tests were carried out in comparison to the Nikon D3, some also in comparison to other Nikon cameras. No comparison was made with equipment of competitive brands. I own several Nikon lenses and thus I'm only interested in which Nikon camera serves my needs best. In my opinion, photographic equipment is only a tool and a good photographer makes a good image, unrelated to whether the brand mark on his tool says "Nikon" or "Canon".

 
 

I was very (pleasantly) surprised when the D800 was announced. Its name is very deceiving, since one could easily presume that it's the successor to the D700, which is far from the truth. The D800 is exactly what many Nikon photographers have been waiting for in vain, since the introduction of the D3X (2008) – an image sensor with high resolution in a small and relatively affordable camera. It's an entirely new camera class for Nikon, which the competition offered and successfully promoted for quite some time. Considering that it boasts unbelievable 36 MP, it would be far more fitting to call it D4X, rather than D800... Some D700 owners, who were waiting to upgrade their cameras, might be disappointed since the D800 offers "only" 4 frames per second in full FX format, which is less than the D700. These photographers will have to face the truth that things have changed. In the last generation of cameras, the D700 represented a smaller (and cheaper) D3; those who wanted more resolution had to dig deeper into their pockets to get the D3X. It seems like the recent generation turned things upside down: we got a "smaller D4X", those who need speed and high ISO will need to splurge on the D4. Be that as it is, a big group of photographers is infinitely thankful to Nikon for introducing the D800.

 
 

The moment I read the specifications of the coming D800 on the internet, I knew that this camera would be an underwater photographer's dream come true; the camera I've always been waiting for. I always wanted the image sensor of the "small" Nikon D7000 in a more professional body with a better autofocus, and that's exactly what I got! The DX crop of the FX image sensor featured in the D800 includes almost exactly the same amount of pixels (15.3 MP) as the sensor of D7000, plus a bonus of additional 21 MP to full FX format! The body of the D800 is without a doubt much more professional than that of the D7000 and in addition to that it shares the same improved autofocus system as the D4, which is of utmost importance for an underwater photographer. It seems like the D800 is the new "ideal" camera for underwater photography, which has both the usable DX and FX format at the same time!

Some may find it weird - why would I even want a camera with the DX image sensor, when FX sensors are proven to have better characteristics? In truth the small DX sensor has quite a few advantages in underwater photography, like more corner sharpness in wide-angle photographs, what is known from the dome port theory and what I've successfully proven with an extensive test; besides that it offers better conditions for "super macro" photography, since the aspect ratio 1:1 means a smaller crop in reality than with a bigger image sensor.

 
 

As soon as the first pre-production sample of the D800 arrived in Slovenia I asked to borrow it from Nikon Slovenia and tested it for five days in February 2012. When I first held it in my hands, I was slightly disappointed by its relatively light weight. It felt too "plastic", the buttons were more loose and shaky comparing to those on the D3 and I felt that it's also less protected against weather conditions than the D3. Considering the price difference between a (once new) D3 and a D800 is almost double, I figured it has to show somewhere. Obviously I was a tad too pampered with Nikon's "single digit" professional models... But the initial disappointment was soon forgotten, when I started to play with the camera and then analyze the photos on a 30" screen. With every shot I made my affection to the camera grew and after the agreed five days testing period was over I found it difficult to hand back the camera. I had to wait almost a month before the first shipment arrived in Slovenia that I have finally bought my own D800 on the very first day of sales.

 
 
The test
 
 

As already mentioned in the introduction, my test is based on comparisons with some other Nikon cameras. I selected the following cameras to be used in the test:

Nikon D3 (my own): This camera serves as a kind of standard and most of my comparisons of the new D800 are made with the D3.

Nikon D2X (my own that I use in underwater photography): Some might find this comparison pointless, useless or even unfair, since there are two generations between these two cameras. In the time of testing the D2X is 8 years old and in digital photography that sounds like an eternity. It's clear that the D800 is almost in all aspects a better camera (except in its robustness and battery life). I decided for this comparison, to see what I would gain, if I exchange my D2X with the new D800 for underwater photography.

Nikon D3X (borrowed): the D800 is in a way the replacement for D3X, so I was interested in seeing the difference between the older 24 MP and the newer 36 MP image sensor.

Nikon D4 (borrowed): the D4 is currently said to have the best picture quality of all Nikon cameras at high ISO setting, therefore I was very interested how much the image sensor of the D800 will fall behind the D4 in low light conditions.

Nikon D7000 (borrowed): as I already mentioned the D800 and the D7000 have a very similar pixel density, consequently they should have many very similar photographic characteristics. In the test I wanted to check if this is true.

I borrowed the D4 and D3X on a rainy Sunday – obviously not an ideal day for testing, but in sunny weather it would be more difficult to borrow them. The D7000 was unfortunately not available at that time. I carried out the majority of my comparative tests on that day. In order to achieve objective comparison, it's best to test all cameras at approximately the same time in constant conditions. The noise test was carried out indoors under very controlled conditions and therefore I could test the D7000 relatively objectively some days later.

For an objective assessment of the photos a good monitor is crucial. If your monitor does not show a difference between the lower light gray and dark gray tones, you won't be able to see some of the key differences in the test images. The Nikon D800 has an extremely broad dynamic range, and therefore a professional screen is especially important when assessing photos made with this camera. I myself use a calibrated 30" HP ZR30W monitor.
 
 
 
 
Resolution
 

At the time of writing the D800 offers the highest image sensor resolution available on the market in its class. The size of the image sensor is 35.9 x 24.0 mm and it produces images at resolutions up to 7360 x 4912 pixels (36.15 MP), which means 62,3 x 41,6 cm large prints, if they are printed without interpolation at 300 dpi. Its DX crop enables 4800 x 3200 pixels (15.36 MP), which means 40.6 x 27.1 cm prints. That is a greater resolution than the resolution of my D2X on its full DX format (4288 x 2848 pixels, 12.21 MP, 36.3 x 24.1 cm)! In addition to that, the D800 offers two more formats: 5:4 (which I personally find rather ugly and I will never use it) and the 1.2x crop. The latter records photos at 6144 x 4080 pixels (25.07 MP) or 52.0 x 34.5 cm prints (at 300 dpi, without interpolation).

I will most likely use the DX format for wide-angle underwater photography, but before making a final decision, I need to carry out more comparative tests between DX and FX wide-angle lenses with different dome ports (which I will conduct when I get my underwater housing). For macro underwater photography I will use solely the FX format, same goes for super macro, in both cases I prefer to crop the photos later in the computer. I don't see a reason to limit myself to the DX format with macro photography (and maybe miss a great shot of a larger animal), since I can more easily make crops later in a computer to achieve the desired composition. One of the advantages of a high image sensor resolution is the broad cropping option.

The 1.2x format represents another interesting possibility. Even though it's smaller than the FX format, it still produces photos of 25 MP (which is even slightly more than photos of the D3X!), it speeds up the camera from 4 to 5 frames per second and "extends" the telephoto lens for a factor of 1.2 – a possibility that shows the potential of the D800 as an action camera. While shooting action scenes, we are able to see the happening outside of the 1.2x format (there is a 3 mm margin between the 1.2x and the FX format), which helps for successfully framing and anticipating the next move of the object.

I tested the practical meaning of different image sensor resolutions with a simple test. For this test I chose four cameras with different resolutions: D3 (12 MP), D4 (16 MP), D3X (24 MP) and D800 (36 MP).

The transition from 12 MP to 16 MP means an approximately 15% increase in resolution (square root of quotient of sensor resolutions), the transition from 12 MP to 24 MP accounts for an approximately 42% increase and from 12 MP to 36 MP it's an approximately 73% resolution increase. But all of these are just increases of the image sensor resolution, not of the picture resolution! The latter also depends on the lens resolution. One could simply conclude, that the resolution of the photographic system (sensor + lens), depends on the weaker link – if the sensor has a lower resolution than the lens, the final resolution will equal that of the sensor and vice versa if the lens is the weaker link. Unfortunately that is not the case, it's even worse. Picture details never fall ideally on the sensor's pixels, but rather completely randomly. The system resolution can therefore be roughly estimated with the following equation:

1/R = 1/RS + 1/RL

R represents the system resolution (and consequently the final resolution of the photograph), RS represents the image sensor resolution and RL the lens resolution. Resolution is measured in line pairs per millimeter (lp/mm), where a line pair consists from a white and a black line. The image sensor resolution of the Nikon D800 is 102.5 lp/mm (7360 : 35.9 : 2 – the number of pixels on the longer side of sensor divided by the length of the longer side, divided by two) or approximately 100 lp. In the same way we can calculate the image sensor resolution for the other test cameras: D3 (59 lp/mm), D4 (68 lp/mm) and D3X (84 lp/mm). If we presume that the lens's aerial resolution (that is the ideal image of the lens, which the lens draws into the air and is thus independent on the sensor resolution) is 100 lp/mm and apply these numbers to the equation above, we find that the photo resolutions of the tested cameras are:

D3:       37 lp/mm
D4:       40 lp/mm
D3X:    46 lp/mm
D800:   51 lp/mm

Not too impressive now, is it? A photo made with the D800 has only a 38% higher resolution than the one shot with the D3 and not 73% as was calculated before! To make things worse, the previously used equation does not take into account the anti-aliasing filter, which further reduces the resolution. However it's important to remember that a lens with the resolution of 100 lp/mm is a bad lens and the typical aerial resolution of a professional lens is 200 lp/mm or more. While shooting with the test cameras equipped with a professional lens (200 lp/mm) we get the following results:

D3:       46 lp/mm
D4:       51 lp/mm
D3X:    59 lp/mm
D800:   68 lp/mm

A two times sharper lens causes a photo of the D800 to be 48% sharper than the one from the D3. These numbers clearly show how crucial the lens sharpness is for a sharp final photograph. And vice versa: when testing how sharp certain lenses are it is crucial to use an image sensor with the highest possible resolution in order to diminish it's influence on the overall measurement. For this reason I believe that the D800 will be the perfect camera for lens testing!

 
 
For the resolution test I chose the AFS Micro-Nikkor 60 mm f/2.8 lens, which I find to be one of the sharpest lenses in my collection. I used aperture f/5.6 in order to eliminate possible focus errors while keeping the aperture open enough to prevent the diffraction effect, which again reduces sharpness of the image. I shot my object from the exactly the same distance and in the middle of my composition I placed the test bar with differently broad lines printed on it. All cameras had completely identical picture parameters (sharpness level, etc.). After shooting the photos I subjectively assessed on my computer monitor when the lines dissolve into grayness. The numbers on the testing bar do not have a quantitative meaning, but serve only as a means of camera comparison.
 
 

According to my subjective observation, the lines dissolved into a unified gray mass at approximately the following numbers:

D3:       80
D4:       90
D3X:    110
D800:   130

Considering that the ratio between these numbers and the ratio of the imagine sensor resolution is very close, we can conclude that the AFS Micro-Nikkor 60 mm f/2.8 lens is truly very sharp and perfectly capable of using the high resolution of D800's image sensor.

In all test photos the undesired moiré effect can be noticed (instead of grayness there are certain colorful patterns), which points to the fact that Nikon is using relatively weak anti-aliasing filters. Seeing as the moiré effect is rarely problematic in practice, I believe Nikon made a very good choice with the filter selection. Further details about the anti-aliasing filter will be mentioned in the D800E chapter.

The photos below, both shot from the same point with the same focal length, clearly show what D800's resolution means in practice (in comparison to the resolution of the D3):
 
 
 
 
Chromatic aberration (CA)
 

Chromatic aberration (CA) is a familiar lens aberration, when more or less colored boundaries between bright and dark surfaces appear on the peripheral part of the photograph. The aberration occurs because lens elements have a different refractive index for different wavelengths of light. Lens constructors try to neutralize chromatic aberration with several combinations of glasses and lens geometrics, but it seems to be almost impossible to entirely suppress it by optical means. Luckily CA can easily be removed with photo editing software.

In 2007 Nikon pleasantly surprised us with the launch of the D3 and D300 cameras, since these two cameras already featured built-in algorithms for picture processing, which were previously part of the Capture NX software. With this move, they managed to largely eliminate CA and one has to admit that the JPG photos published straight from the camera, practically didn't exhibit this aberration. But that was back then, on 12 MP image sensors...

When I was playing with my new D800, I noticed a considerable amount of CA in some JPG photos. I immediately wanted to get to the root of this problem and made some quick comparative shots with the D3. Now I've noticed some CA even with the D3 in similar shots, but substantially less. When I borrowed the D4 and D3X for testing purposes I also decided to test the CA in order to discover how different image sensor resolutions influence on this type of aberration.
 
 
For the test I used my AFS Nikkor 24-70 mm f/2.8 lens. I framed exactly the same shot with all cameras at the same focal length of 24 mm and aperture f/5.6. I framed my photo in a way that the kiwi-tree bud in the upper left corner was in strong contrast to the bright grey cloudy sky. All settings were the same in all cameras and for the photo quality setting I used RAW + JPG L Fine. I developed the RAW photos in the software Capture NX2 into two images – in one I intentionally did not remove the CA (I received a picture as the lens makes it), while in the second image I removed the CA. Additionally, I decided to develop the RAW photos also in Adobe Lightroom, version 4 (LR4), which already supports the new cameras D4 and D800.
 
 

When observing the unedited photos (NEF, CA not fixed) we see that the amount of CA truly is quite proportional to the image sensor resolution. Sadly this does not hold true for JPG photos made by the cameras themselves. The built-in camera corrections are minimal and in my opinion insufficient. I've never noticed this problem with the D3 before, but with the D800 it is very disturbing, as it is with the D3X and slightly less with the D4. Even developing a RAW photo in Capture NX2 doesn't fully remove CA. But I was especially surprised that Lightroom LR4 fixed this aberration better than Nikon's own NX2 software!

Personally I find it unacceptable that Nikon did not put sufficient efforts in removing such an unpleasant optical aberration in professional cameras like the D800 (or the D3X for that matter). As we will see later, the camera features an array of tools, which improve picture quality, such as vignetting correction, ADL (active D-lightning) or even lens distortion. All these tools can be turned on or off according to the user's preference in the process of making a JPG photo. In case that the process of reducing CA influences picture sharpness similarly as the distortion correction (which I doubt) the camera should include it as an option for the user to decide whether to use it or not. Simply we cannot accept the fact, that such a state-of-the-art camera can't produce a JPG photograph without visual CA unless we edit it subsequently with a software afterwards. In my opinion this is one of the greatest flaws of this otherwise exceptional camera (and obviously also of the D3X).
 
 
Page 2 (Noise)
Page 3 (Picture Control, ADL and HDR, Vignetting control, Distortion control)
Page 4 (Diffraction and depth of field, Autofocus, White balance (WB) and monitor)
Page 5 (Nikon D800E, What do I find problematic with the D800?, Conclusion, Post Scriptum)