In-camera processing of long-exposure RAW data

Started Jan 21, 2010 | Discussions thread
OP Marianne Oelund Veteran Member • Posts: 7,779
The Sins of the Algorithm

jim stirling wrote:

The reality of the situation seems that it is only of relevance to those taking some form of photography where truly accurate image data was critical , perhaps astrophotography for scientific analysis as opposed to about 99.99% of photography that has aesthetics or capturing the moment as its objectives. And frankly unless you are in this probably microscopic niche of photographers who this would effect , the relevance to the vast majority of photographers is insignificant.

There are a great many details ignored by the vast majority of photographers. That does not make them insignificant.

The hot-pixel algorithm treats every single pixel in an image (except for the two border rows/columns, which never end up in camera JPEG or raw converter output anyhow), and adjusts every one it finds that has a higher value than any of its 8 same-channel neighbors. That means in a 12Mpix image, even one which contains no hot pixels at all, about 50,000 pixel values will be affected, on average. If an image contains many very fine details, that number will go up substantially.

If that doesn't matter to you, that's fine, but it annoys me to no end, especially when a simple change to the algorithm could avoid all of this mess. To me, the fact that Nikon have left this utterly simple-minded and destructive algorithm in their top-line cameras costing $5K US and up, is completely inexcusable.

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