Understanding RAW Files

Understanding RAW Files

Understanding RAW Files

1. What is NEF(RAW) mode?

Nikon refers to images saved in the RAW format as NEF (Nikon Electronic Format) files. RAW mode allows you to shoot an image as a raw image. A raw image is the pure data directly saved from the camera's image sensor onto the card. With other image formats, the camera processes the raw data and converts it to TIFF or JPEG, but with RAW mode, the pure data is saved and can be edited later. Since no corrections have been made, there is more opportunity to edit the file later. RAW images are larger than JPEG but not as large as TIFF.

2. RAW images and 16-bit files

The camera either captures 12 bits of data per colour or 14 bits of data per colour depending upon the camera's analogue to digital circuitry. The table below illustrates the number of shades per colour depending on the bit depth:

8 bits

256 shades of red, blue and green

12 bits

4096 shades of red, blue and green

16 bits

65536 shades of red, blue and green

RAW files are 16-bit files whereas JPEGs are 8-bit files, so a RAW file can contain as many as 65536 levels of each colour whereas a JPEG file can contain only 256 shades of each colour. When an image is saved as a RAW file, the digital camera actually captures 12-bits of colour and steps it up to 16-bits. When saved as a JPEG, the image is stepped down to 8-bits.

 

3. Benefits of shooting in RAW

The histogram of an 8-bit JPEG images will begin to band after applying small amounts of levels and the image will most likely get posterised as an effect. A RAW image preserves the continuous flow of colour tones.

Image
Image
Histogram of a RAW file after applying levels
Histogram of a JPEG file after applying levels

 

Nikon RAW NEF files can be edited in Nikon View Editor, PictureProject, Nikon Capture Editor and Nikon Adobe Photoshop plug-in.

 

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