Epson-ERF

Epson Raw Format

image/x-epson-erf Released 2004 · by Seiko Epson Corporation

The image/x-epson-erf MIME type represents the Epson Raw Format (ERF), a proprietary digital camera raw image format created by Seiko Epson Corporation. Built on top of the standard TIFF/EP architecture, ERF files store uncompressed or losslessly compressed pixel data directly from the camera's image sensor. This format is most famously associated with the Epson R-D1, released in 2004 as the world's first digital rangefinder camera (co-developed with Cosina). Because Epson largely exited the consumer digital camera market shortly after, the format is historically significant but effectively obsolete in modern production workflows.

Photography & Raw Imaging ✦ HDR Production Ready

Technical Specifications

MIME Type

image/x-epson-erf

Extensions

.erf

Container

TIFF/EP

Compression

Uncompressed & Lossless JPEG (ITU-T81)

Algorithms

NoneLossless JPEG

Color Depth

12-bit (Per Channel)

Metadata

EXIF XMP

Capabilities

Transparency

Animation

Progressive Loading

Alpha Channel

HDR Support

Official Specification

Aliases: image/erf

Magic Bytes & HTTP Headers

File Signature (Magic Bytes)

49 49 2A 00 or 4D 4D 00 2A

ASCII: II*\x00 or MM\x00*

HTTP Headers

Content-Type: image/x-epson-erf

HTML Accept Attribute

accept="image/x-epson-erf, .erf"

Browser Support Matrix

Browser	Status	Min Version
Chrome	Not Supported	—
Firefox	Not Supported	—
Safari	Not Supported	—
Edge	Not Supported	—
Internet Explorer	Not Supported	Legacy

Advantages & Limitations

Advantages

Preserves original raw sensor data, allowing extreme recovery of highlights and shadows compared to in-camera JPEGs
Utilizes the standard TIFF container structure, making it relatively easy for open-source software (like dcraw and LibRaw) to parse and decode

Limitations

Completely obsolete proprietary format tied to a defunct line of digital cameras
Requires parsing EXIF metadata to differentiate it from standard TIFF files programmatically
Cannot be natively viewed in web browsers or standard operating system image viewers without specialized codecs

Developer Code Snippets

import magic
# Libmagic will identify ERF files as standard TIFFs due to the shared 49 49 2A 00 / 4D 4D 00 2A header
print(magic.from_file('photo.erf', mime=True)) # Outputs 'image/tiff'

const FileType = require('file-type');
const type = await FileType.fromFile('photo.erf');
console.log(type?.mime); // Usually resolves to 'image/tiff'. Extension checking is required for 'image/x-epson-erf'.

import (
    "bytes"
    "net/http"
)
// Native Go HTTP detection reads the TIFF magic bytes and returns 'image/tiff'.
// Advanced metadata parsers are required to read the Epson MakerNote EXIF tags.

$mime = mime_content_type('photo.erf');
echo $mime; // Standard PHP installations will resolve this to 'image/tiff'

File Detection Steps

How to programmatically detect a image/x-epson-erf file by reading its raw bytes:

1 ERF files begin with the standard TIFF little-endian (49 49 2A 00) or big-endian (4D 4D 00 2A) magic bytes.
2 Because ERF shares its header exactly with standard TIFF files and other TIFF-based raw formats, standard file sniffers will initially identify it simply as 'image/tiff'.
3 To definitively identify an ERF file, a parser must read the TIFF Image File Directory (IFD) EXIF tags and locate the Epson-specific 'MakerNote' string identifying the camera model.

Software Support

A

Adobe Lightroom Classic / CC

D

Darktable

R

RawTherapee

ImageMagick

Conversion Tools

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Interactive iframe Widget

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JSON API

All data on this page is available as a free, open JSON API. Use it in your project, documentation, or tooling.

GET https://freewebptojpg.com/mime/image/epson-erf.json Open JSON

Free to use

No auth required

CORS enabled

Use from any domain

Cached 24h

Cache-Control headers set

Frequently Asked Questions

What is an Epson ERF file?

An ERF file is a raw image format created by Epson for its digital cameras, most notably the legendary Epson R-D1 digital rangefinder. It contains unprocessed sensor data, allowing photographers to adjust exposure and white balance without quality loss during post-processing.

Is the Epson ERF format still used today?

No. Epson exited the dedicated consumer digital camera market many years ago. ERF files are now primarily encountered by vintage camera enthusiasts shooting with the classic Epson R-D1 series or archiving historical photographs.

How do I open or edit an ERF file?

Because it is a raw format, standard web browsers and basic image viewers cannot open it. You must use specialized raw processing software such as Adobe Lightroom, Darktable, RawTherapee, or Capture One to 'develop' the image into a standard JPEG or TIFF.