EXR to NEF Converter

Encoding: the EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file; NEF uses uncompressed, lossless compressed, lossy compressed, or High Efficiency on recent Z bodies, and the download is a Linear DNG: demosaiced 8-bit RGB with the colour matrices raw editors need.

Bit depth: 16-bit half or 32-bit floating point per channel in the EXR; NEF allows 12 or 14 bits per channel, and the DNG written here has 8 bits per channel, linearised. Floating-point values are mapped to 8 bits per channel, and anything brighter than white clips.

Colour: scene-linear RGB, often ACEScg or linear Rec.709 in the EXR; NEF supports camera RGB from a Bayer mosaic, written here as 8-bit sRGB.

Transparency: the EXR stores it as an A channel stored like any other channel; the DNG has none, so transparent areas are filled with the colour you choose.

Other images: the EXR can hold extra channels (depth, normals, render passes) and multiple parts; only the main image is converted.

Metadata: the EXR can carry named header attributes such as chromaticities, timecode and camera data; NEF can carry EXIF and Nikon maker notes, partly encrypted, plus a thumbnail and a larger preview, but nothing is copied across.

OpenEXR is the high dynamic range format of film visual effects. It stores half or full floating-point channels in linear light, plus any extra render passes, and is the working format of compositing pipelines.

An EXR starts with the magic number 76 2F 31 01 and a version field, then a header of named, typed attributes (channels, compression, dataWindow, displayWindow) and a table of offsets to scanline or tile blocks.

EXR files usually come from 3D renderers and compositing in Nuke, Blender, Houdini, After Effects and DaVinci Resolve.

NEF is the raw format of Nikon cameras, from the D1 to the current Z series. It stores 12 or 14-bit sensor data, uncompressed or compressed, with a JPEG preview the camera renders using its Picture Control.

NEF is TIFF-based: the first directory usually holds a small thumbnail, and sub-directories hold the sensor data and, on current bodies, a full-size JPEG preview. Nikon's maker notes are a TIFF structure of their own, and since the D2X their white-balance block is encrypted with a key derived from the camera's serial number and shutter count.

NEF files come from Nikon DSLRs (D-series) and Z-series mirrorless cameras.

Forms and workflows that ask for NEF usually feed a raw editor, and each of those opens DNG as well, so the DNG can take the NEF's place. Keep the EXR if you only need to view or share the picture.

What NEF offers when it comes straight from the camera: Lossless compressed mode with no data loss; Picture Control recorded so Nikon NX Studio can reapply it; 12 or 14-bit sensor data. Its drawbacks: Partly encrypted maker notes; The lossy compressed mode discards some sensor data; Large files on high-resolution Z bodies.