Banding and artifacts

[Andre]

FPVPro claims the following: "The result is one of the most accurate and faithful color reproduction available in any viewer, especially on high-end wide gamut display monitors, with the smoothest possible gradients and no artificial banding effect introduced by less exacting software applications."

However with both the Codec (viewing with Windows Photo Viewer) as well as with FPVPro I get artifacts and banding when viewing RAW files. In FPVPro I tried disabling GPU acceleration, ICC profiling, using different profiles, yet still I get the artifacts.

A view specs from my side that might provide some clues:
Windows 7 64bit
Monitor: NEC 2690WUXi (native Adobe RGB colourspace)
GPU: Radeon 4870 1GB

I have also tried this on a laptop with an NVIDIA NV3100M GPU, an TN screen, yet the issue is still there.

So my question is, what's the deal with that? Known issue? Something on my side?


I've included the original RAW file and two screenshots, one from FPVPro and one from CR for comparison. This might seem like an extreme example, but it's there and it's rather distracting when viewing this type of photos.

RAW file
http://localhostr.com/file/VN9PoSl/_ASF0461.NEF (12MB)

FPVPro
http://i.imgur.com/PdFbe.png

Camera Raw
http://i.imgur.com/0CSIm.jpg

[Axel]

Your NEF file displays within expectations here, nothing special except that there is not that many black levels beween super-super-dark and super-dark, so some amount of posterization effect is to be expected in very dark gradients, in particular knowing that the image displayed is a 8-bit JPEG preview. You can press the 'R' key in FastPictureViewer while the image is on-screen to display another version based on the converted raw data. Chances are that it will be different.

Since the NEF preview shown by default is a JPEG made by the camera itself, any artifact that you see are the result of what was written by the camera, possibly magnified by your color management settings (monitor calibration and monitor profiling). ACR creates an entirely different image from the raw data so the result is bound to be different.

Now, some people see banding in Nikon's own officially published D3 sample images so I guess it's a mix of expectations and understanding of the technology limitations, and how to make best use of it.

[Andre]

Thanks for the reply. I wasn't aware that FPV was showing the preview of the RAW file and that there was a hotkey to process the RAW data. When in RAW mode it does render much better, alas the rendering takes slightly longer than usual. Is processing RAW file in this RAW mode takes advantage of the GPU or is it all done by the CPU?

[Axel]

Raw decoding is done by our NEF codec on the CPU, with some level of parallelism so it runs a bit quicker on multicore processors (and is pretty fast by any standards...) but raw processing is always going to be slower than unpacking JPEG data.

The JPEG preview written by Nikon cameras is a full-size image of very good quality. It is usually more than sufficient to judge the quality of a photo, except perhaps in extreme cases (exposure off by several stops), where only CaptureNX can rescue the file.