Nikon D4s With the recent introduction of Nikon's new flagship D4s full frame camera, came a new file format called sRaw. The photography forums have been buzzing about this new file format. What is it and how does it work? Will it be of any real benefit to quality image seekers? With image files getting bigger as sensor technology moves forward, Nikon I'm sure felt the need to find a way to reduce file size. Reducing file size will help with on-going storage problems as well as requiring less processing power to work on the files. In a nutshell this is what happens with a sRAW file.
It contains not RGB but YCbCr data much like a JPEG;
The data is 11-bit;
The tone curve is applied to the data;
The in-camera white balance is applied to the data;
The pixel count is 4 times less than with regular NEF files;
The color information is shared between two adjacent pixels (in other words, chroma is recorded for each other pixel);
The file size is insignificantly smaller than full resolution 12-bit lossy compressed NEF;
Compared to a regular NEFs the data needs additional processing (linearization) while converting it to a TIF/JPEG, that may cause additional problems during the conversion as well as some additional computational errors;
There is some loss of color accuracy in shadows, which negatively affects the usable dynamic range if color accuracy is important.
For more detailed information on sRAW files see www.rawdigger.com. They have a very detailed report on this new file structure there. Credit goes to them for the above information.
It contains not RGB but YCbCr data much like a JPEG;
The data is 11-bit;
The tone curve is applied to the data;
The in-camera white balance is applied to the data;
The pixel count is 4 times less than with regular NEF files;
The color information is shared between two adjacent pixels (in other words, chroma is recorded for each other pixel);
The file size is insignificantly smaller than full resolution 12-bit lossy compressed NEF;
Compared to a regular NEFs the data needs additional processing (linearization) while converting it to a TIF/JPEG, that may cause additional problems during the conversion as well as some additional computational errors;
There is some loss of color accuracy in shadows, which negatively affects the usable dynamic range if color accuracy is important.
For more detailed information on sRAW files see www.rawdigger.com. They have a very detailed report on this new file structure there. Credit goes to them for the above information.
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