NEF to BMP Converter
Convert NEF to BMP in your browser. The largest embedded JPEG is converted; older bodies sometimes stored only a reduced preview, which then sets the output size. No raw development happens here. You get an uncompressed 24-bit BMP, or 32-bit with alpha when the image has transparency. Nothing is uploaded.
- Processed locally
- No upload, no wait
- No sign-up
- No watermark
Drop images here
or choose files · paste with Ctrl/⌘ V
RAW expected · other image formats also work
How to use NEF to BMP
- 1
Add your NEF files: drop them here, choose them, or paste from the clipboard.
- 2
There is nothing to tune: the BMP is written uncompressed. Resizing and rotating are under More options if you need them.
- 3
Click Convert. Each file is decoded and encoded in a background thread on this device.
- 4
Download the .bmp files one at a time or together as a ZIP.
Why use Aback Images for nef to bmp
Where the BMP goes next
BMP opens in every operating system and browser.
BMP next to NEF
The BMP stores the camera preview's pixels uncompressed, so it can be as large as the 20 to 60 MB raw file, or larger, depending on the preview's resolution.
No new artefacts
The preview inside the NEF is a camera JPEG; the BMP stores its decoded pixels uncompressed, so this step adds no compression damage of its own.
Processed on your device
Your images are decoded, edited and encoded inside this browser tab by Web Workers. Nothing is uploaded to a server.
NEF vs BMP
What changes from NEF to BMP
Encoding: the NEF uses uncompressed, lossless compressed, lossy compressed, or High Efficiency on recent Z bodies; BMP uses usually none; RLE for some 4 and 8-bit files, and the download is an uncompressed 24-bit BMP, or 32-bit with alpha when the image has transparency.
Bit depth: 12 or 14 bits per channel in the NEF; BMP allows 1, 4, 8, 16, 24 or 32 bits per pixel, and the BMP written here has 24 or 32 bits per pixel. The sensor's 12 or 14 bits are not used: the 8-bit camera preview is converted.
Colour: camera RGB from a Bayer mosaic in the NEF; BMP supports RGB or an indexed palette, written here as 8-bit sRGB.
Metadata: the NEF can carry EXIF and Nikon maker notes, partly encrypted, plus a thumbnail and a larger preview; BMP can carry nothing beyond the header's resolution fields (and a colour profile in rare V5 headers), but nothing is copied across.
About NEF
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 usually come from Nikon DSLRs (D-series) and Z-series mirrorless cameras.
About BMP
BMP stores raw, uncompressed pixels. Files are huge but trivially simple, which is why some legacy Windows software, embedded displays and printers still ask for it.
A BMP is a 14-byte file header ('BM' and the offset to the pixels), a DIB header (40 bytes, or 108 and 124 bytes in the V4 and V5 versions that add colour masks and alpha), an optional palette, then pixel rows padded to 4 bytes and normally stored bottom-up.
When converting NEF to BMP makes sense
BMP is the better choice for legacy software and embedded systems that require it, while NEF suits editing Nikon photos in a raw developer.
BMP strengths: No compression artifacts; Read by very old and very simple software. Drawbacks to weigh: Enormous files; Poor support for transparency; No metadata.
Limitations
- Nikon's lossy compressed NEF mode discards some sensor data in camera; the preview used here is not affected.
- A BMP is uncompressed, about 3 bytes per pixel, or 4 with transparency, so expect a large file.
- Some older programs ignore the alpha channel of a 32-bit BMP and show transparent areas as black or white.
More conversions
Related tools
Convert BMP to NEF in your browser, saved as a Linear DNG, the raw file every NEF editor also opens. Batch, private, no uploads.
Convert NEF to JPG in your browser, made from the full-size preview your Nikon camera stored in the file. Batch, private, no uploads.
Shrink JPG, PNG, WebP, AVIF and GIF files with MozJPEG, OxiPNG and modern codecs, with a live before/after preview.
Resize to exact pixels, a percentage or a longest side, with Lanczos3 and Magic Kernel resampling. Batch ready.
Strip EXIF, GPS, XMP, IPTC and comments losslessly. Pixels are never re-encoded for JPG, PNG and WebP.
Convert between 34 image formats in bulk: HEIC, WebP, AVIF, JPEG XL, PNG, JPG, GIF, TIFF, SVG, ICO, PSD, RAW and more.
Frequently asked questions
Does converting NEF to BMP lose quality?
BMP is written uncompressed, so the pixels are stored exactly as decoded. Those pixels come from the camera's JPEG preview, so its compression stays, but nothing new is lost. The sensor's 12 or 14 bits are not used: the 8-bit camera preview is converted.
Which apps open BMP files?
Every operating system and browser.
Are my images uploaded anywhere?
No. Processing happens inside your browser with WebAssembly and Web Workers. The site only downloads the app code and codecs; your files never leave your device. You can confirm this with the live upload counter on the tool, or in your browser's network panel.
Can I process many files at once?
Yes. Drop a whole selection or folder. Files are processed in parallel on several worker threads, each result can be downloaded on its own, and everything can be saved as one ZIP.
Is it free? Is there a file limit or watermark?
It is free with no account, no watermark and no daily limit. The only limit is your device's memory: very large images (over roughly 100 megapixels) may be refused to keep the tab from crashing.