Picture Batch NEF to JPG
NEF to JPG
NEF is Nikon's raw format, and it has accumulated many internal variations: uncompressed, Huffman-compressed with a lossy curve, lossless-compressed, high-efficiency, and reduced-size variants. Support depends on the exact body and compression mode; known files are decoded as sensor data, while an unsupported combination fails explicitly.
Drop NEF images here
NEF files — or any of PNG, JPEG, WebP, AVIF, BMP, ICO, TIFF, GIF or camera raw (CR2, CR3, ARW, DNG, RAF, ORF, RW2). Everything runs on this device.
Your images never leave this device. They are decoded and re-encoded by your own browser, and the security policy on every page blocks this site from sending them anywhere.
Lossy, no transparency, opens absolutely everywhere, small for photographs.
The standard range for photographs. Hard to distinguish from the original.
Images keep their original dimensions.
JPEG cannot store transparency. Nothing in the queue currently has transparent pixels, so this has no effect yet.
Exif is carried across where both formats can hold it. Nothing currently in the queue has any.
Every pixel gets its two missing colours interpolated from its neighbours, at the full sensor resolution. The slower and more detailed option.
The value your camera recorded when the shutter fired — what you saw on the back of the camera.
Camera, lens, exposure and capture time are written into the JPEG when those fields are present. The file details show whether GPS data exists, but coordinates are deliberately not written, and colour comes out as sRGB.
What happens to your image
Expect a much smaller file than a lossless source, at the cost of some detail.
| Property | Outcome |
|---|---|
| Transparency | Preserved: NEF images have no transparency to lose. |
| Image quality | Partly preserved: JPEG is lossy: the image is re-compressed and detail is discarded to make the file smaller. The quality control decides how much. |
| Colour | Partly preserved: Converted to sRGB. Decoding an image colour-manages it into the browser's own space, so the output is sRGB and is left untagged, which every viewer reads as sRGB. A wide-gamut source is reported before conversion. |
| Exif metadata | Preserved: Carried across if you leave metadata switched on, or removed completely if you switch it off. Camera, date and any location tag travel together. |
| Orientation | Preserved: Applied to the pixels, and the tag is reset to upright afterwards so nothing rotates the image a second time. |
Nikon's compression, and what "12-bit lossy" actually means
For twenty years Nikon's default has been compressed NEF: the sensor readings are passed through a curve that spends fewer values on the highlights — where the eye is least sensitive to steps — and then Huffman-coded. It is lossy, and it is the reason a compressed NEF is roughly half the size of an uncompressed one.
The difference is usually hard to see, but it can appear in a heavily lifted shadow with a strong colour gradient. LibRaw applies its implementation of Nikon's stored curve while decoding; for colour-critical work, compare against the Nikon software you trust.
The reduced-size NEF variants are a different matter: those hold already-demosaiced pixels, so there is no colour filter array left to interpolate. The queue says which kind it found.
The lens is in there, and it comes across
Nikon records the lens, the focal length, the aperture, the shutter speed and the ISO in its own maker-note structure. A converter that copies metadata blocks across finds nothing portable to copy, which is why so many converted raw files arrive with no camera information at all.
Those fields are read here and assembled into a standard metadata block, so the JPEG carries the camera, the lens and the exposure. The capture time comes across as well, which matters more than it sounds: a photo library sorting by date is useless if every converted file claims to have been taken on the day it was converted.
A folder at a time, with the queue doing the thinking
Each raw decode holds the sensor frame, a four-channel working image and the finished pixels at the same time, which for a 45-megapixel Z8 file is comfortably over 700 MB. Running several of those at once because the machine reports eight cores is how a browser tab gets killed halfway through a batch, so how many run in parallel is decided from the device rather than from a fixed number.
The queue tells you what each file will cost before it starts, warns you before a batch that will not comfortably fit, and drops individual files to half resolution rather than attempting something that will fail. One unreadable file fails on its own row with an explanation and everything else carries on.
If something goes wrong
"The sensor data in this file could not be decoded."
A body newer than this decoder, or Nikon's high-efficiency raw, which uses a licensed compression that a WebAssembly build cannot include.
What to do: Set the camera to lossless-compressed or uncompressed raw if you can. For existing files, Adobe's free DNG Converter produces a DNG that converts here without needing per-model support.
The image is dimmer or flatter than expected.
No picture style is applied. Nikon's Standard and Vivid profiles add contrast and saturation that a converter has no way to know you wanted.
What to do: Expected, and it is why raw editors exist. For a neutral starting point this is correct; for the camera look, develop the file in software that has Nikon's profiles.
A .NEF file is identified as an ordinary TIFF.
It is one. Some Nikon software writes TIFF files with a .nef extension, and identification here comes from the contents rather than the name.
What to do: Nothing to fix — it converts through the TIFF path, which is the correct one for a file that has already been demosaiced.
Questions
Does NRW work too?
Yes. NRW is what Nikon's Coolpix compacts write, and it is read here alongside NEF. Both are recognised from their contents rather than their extension.
Will the converted JPEG have my copyright and artist details?
If your camera was configured to record them, yes — the artist field comes across. The GPS position deliberately does not: it is shown to you in the file details and left out of the output, because a converted file is usually on its way somewhere.
Can I convert NEF to PNG or WebP instead?
Yes, both. PNG is lossless from the decoder onwards and is the right choice if the image will be edited further. WebP is a good middle ground — smaller than JPEG at the same visual quality, and supported by every current browser.