Image MIME Reference
Nikon-NEF
Nikon Electronic Format
image/x-nikon-nef
VS
PiCture eXchange
image/x-pcx
PCX
A complete technical comparison of Nikon Electronic Format and PiCture eXchange — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.
Equal browser support
Feature Support
| Feature | Nikon-NEF | PCX |
|---|---|---|
| Transparency (Alpha) | ✕ No | ✕ No |
| Animation Support | ✕ No | ✕ No |
| Progressive Loading | ✕ No | ✕ No |
| HDR Support | Yes | ✕ No |
| EXIF Metadata | Yes | ✕ No |
| ICC Color Profile | Yes | ✕ No |
Nikon Electronic Format
image/x-nikon-nef
Extension
.nef
Container
TIFF
Compression
Uncompressed / Lossless Compressed / Lossy Compressed (High Efficiency)
Algorithm
NoneNikon Proprietary LosslessNikon High Efficiency Lossy
Color Depth
12-bit (Per Channel), 14-bit (Per Channel)
Developed by
Nikon Corporation
Released
1999
Magic Bytes
49 49 2A 00 or 4D 4D 00 2A
PiCture eXchange
image/x-pcx
Extension
.pcx
Container
ZSoft Proprietary Header (128 bytes)
Compression
Run-Length Encoding (RLE)
Algorithm
ZSoft RLE
Color Depth
1-bit (Monochrome), 4-bit (16 colors), 8-bit (256 colors), 24-bit (True Color)
Developed by
ZSoft Corporation
Released
1985
Magic Bytes
0A (followed by version, e.g., 0A 05 01 08)
Browser Support Comparison
| Browser | Nikon-NEF | PCX |
|---|---|---|
Chrome
|
✕ | ✕ |
Firefox
|
✕ | ✕ |
Safari
|
✕ | ✕ |
Edge
|
✕ | ✕ |
IE (Legacy)
|
✕ | ✕ |
Nikon-NEF
Nikon-NEF Strengths
- Retains maximum sensor data, allowing extreme recovery of highlights and shadows that would be permanently lost in a JPEG
- White balance, sharpening, and color profiling are saved as metadata instructions rather than 'baked in', meaning they can be completely altered in post-production without degrading the image
- Embeds a high-quality JPEG preview inside the raw file for rapid culling and viewing
Limitations
- Proprietary format means it requires constant updates to raw processing engines every time Nikon releases a new camera model
- Produces very large file sizes (often 20MB to 50MB+ per image depending on sensor resolution and bit-depth)
- Cannot be directly embedded into web pages or used in standard HTML/CSS contexts
PCX
PCX Strengths
- Incredibly simple RLE algorithm makes it very fast to decode, which was historically vital for early 3D video game engines
- Retains crisp, lossless pixel data suitable for pixel art and interface assets
- Well-documented and highly supported by older desktop publishing and image editing software
Limitations
- Extremely inefficient compression by modern standards, producing large file sizes compared to PNG
- Lacks modern imaging features such as alpha channel transparency, EXIF metadata, and color profiles
- Zero support in web browsers; must be converted to PNG for web use
When to choose which format
Nikon-NEF
Use Nikon-NEF when…
- Professional Digital Photography
- Non-destructive Image Post-Processing
- High Dynamic Range (HDR) Imaging Archival
PCX
Use PCX when…
- MS-DOS and Early Windows Graphics
- 1990s Video Game Assets (Textures, UI)
- Retro Computing Archival