The D800 is one of those cameras where one assumes Nikon has chosen an imager that will give priority to the performance of base ISO. While the D800 has surprisingly good high ISO performance, I don’t consider it a priority over base ISO performance.


The D800 offers a base ISO of 100, which can be extended to L1 (ISO 50 equivalent) in third step increments, L0.3 L0.7 and L1. Finally we have a FX sensor that has a base ISO of 100! While the D3 and D3s sensor were all very good with their base ISO of 200, I often wanted, and needed, a lower ISO. Indeed, a Base ISO of 50 would have been ideal, but ISO 100 does just fine. One stop goes a long way, and in terms of long exposures, I often want a longer exposure time.


The L1 setting is basically an overexposed ISO 100 shot, which is then processed internally to simulate an ISO 50 image. Often this results in slightly smoother tones and lower noise levels, especially in the lower mid-tones and shadow areas. On the negative side, it takes away from the image’s highlight recovery headroom. In essence, if the dynamic range of the scene isn’t too high, L1 may just be the best choice. Otherwise, exposing to the right and pulling back in post processing does much the same.

Review:http://www.martinzimelka.com/homepage/Blog/Blog.html

NAVIGATION:

ISO Performance: Part I

These days, more attention is given to high ISO performance than the quality at base ISO. While cameras have come a long way in the past few years, some people suddenly feel they need the capacity of shooting at ISO 25 000. Like it’s something owed to them by camera and sensor manufacturers, and if a camera is incapable of performing at these high ISO values, then it must be an all round rubbish camera. It seems that only a minority of people truly value base ISO performance. And while high ISO performance and great base ISO performance go hand in hand, they are not necessarily directly related.


The interesting thing is, RAW converters such as ACR 6 &7, or NX2, exaggerate the image tone curve to the point where highlights are brighter that they actually are. Processing files in RPP, using a straight tone curve, makes it very obvious how falsely bright other programs render the files. This isn’t necessarily a bad thing, since it’s only beneficial by being aware of how these converters render. Since cameras also employ a form of shooting profile, like “Standard” or “Neutral”, it’s safe to shoot until highlights start to clip. Since the image brightness is slightly contrived, the highlights are not truly clipped and are therefore easily recoverable.

The above image sliders illustrate the remarkable latitude a D800 RAW files has to recover shadow detail (ISO 100).

It should be clear what the sliders are representing; A five stop underexposed image, which is then recovered in a RAW editor with the appropriate +5 exposure correction. The left slider box represents the entire image, and the right slider box represents an actual pixels crop.

The RAW converter used above was Lightroom 4, with only the default chroma noise reduction values applied.


I would regard this as nothing short of impressive!


Below, you’ll find a scene which I overexposed by roughly three stops. The amount of recoverable highlight detail is very also impressive. I would consider the practical limit of highlight recovery to be around 2 stops, otherwise colour transitions start looking artificial. This sample image was also a ISO 100 file.

The ability to push shadow detail and pull highlight detail increases the practical dynamic range of the camera, and I consider this to be more important than images straight out the camera. While my editing is usually very conservative, I do find myself in situations where necessary pushing or pulling is required.

Below is a camera comparison of a scene with a large dynamic range. The ground was poorly lit, and the cloud covered sky was bright. Balancing the brightness of the foreground and the sky meant I had to apply the following adjustments in LR4: Highlights -75, Shadows +100, Clarity +30. The camera profiles used were Camera Neutral, and both cameras were shot at their respective Base-ISO values.

It’s clear to see that the D800 just does better in this situation. The differences are deceptively small, with most noticeable differences in the highlights, but I can assure you the D800 handles those shadow details with a much greater ease. The D700 image has slightly lighter mid-tones, even though exposures were identical and the light was consistent (checked with my hand held meter). The D800 shows less blown highlights, and global contrast is a little lower, which is evident when comparing the details in the foreground. The D700’s image is simply higher in contrast than that of the D800, falling a little short in highlight and shadow detail. Please note, the D800 used in the above comparison was a D800E!

 

The D800 RAW files boast a superior flexibility than D700 RAW files. Shadows can be pushed and highlights can be pulled to great lengths, all while apparent noise levels stay surprisingly low.


On the right is an image taken on a local wine estate. I took this image with my Zeiss Makro-Planar 100/2 ZF attached to the D800. The exposure was 1/60sec at f/8, ISO 100, and I used a tripod and mirror lock-up. My Lightroom 4 settings were...Highlights: -78, Shadows: +67, Whites: -31, Blacks: -2, Clarity: 31.


Click the image to see a before/after image, as well as actual pixel crops. Unfortunately, that day was a little hazy, and the contrast was not the most desirable.

Below is another example of pushing the shadows in post processing. This time, my Shadows slider in LR4 was pushed to +100 (maximum). The original image, seen left of the slider box, was shot at 1/640 sec f/5.6, ISO 100.

The results are very good. While luminance noise levels are higher in the pushed shadow areas, the absence of ugly chroma noise is very pleasing.


The consistent absence of pattern noise is also fantastic!

Significant advances in image quality have been made since the introduction of the D700, which today is still a very good performer. The advances don’t just stop with the practical dynamic range that can be extracted from the RAW files, but also with how the camera handles low light situations at high ISO values, which is covered next in ISO Performance Part II.