14 bit lossless compressed?

Started Feb 8, 2011 | Discussions thread
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antimonite
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14 bit lossless compressed?
Feb 8, 2011

Analysing RAW files from the D7000 that can be downloaded from the net, I found that the 14 bit ones are lossy compressed even though the metadata indicate lossless. Comparisons of picture histograms show that the possible RAW values are reduced at high ISO.

All the files are lossless as seen in the metadata e.g.:

ISO 6400 histogram clearly shows the missing values using ISO 100 as a reference:

Finally a count of the existing values in every channel (red, green, green, blue) show how they initially grow due to the noise, and that they start to decline after ISO 1000 and down to 1/6 of the ISO 100 figures.

Antimonite

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