.NEF

Introduction

NEF is the raw photo format of Nikon’s digital cameras. It holds the data from the camera’s sensor before any processing, together with the camera settings and a JPEG preview. A raw converter turns it into a finished photo.

Nikon has not published the format. Other programs read it by following the work of open source projects that worked out its layout and compression.

Structure

A NEF file is a TIFF file. It begins with a TIFF header and a chain of image file directories (IFDs) of tags. The main IFD and its sub-IFDs point to one or more JPEG previews and to the raw sensor data, which is stored uncompressed or with Nikon’s own lossless or lossy compression. The Exif data carries a Nikon maker note with the camera’s settings, some of it encrypted.

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