ORF File Format (.orf)

An ORF file holds the unprocessed sensor readout from an Olympus or OM System camera in a TIFF-based container with Olympus maker note metadata, and the same extension was used across Olympus compacts, the Four Thirds E-series DSLRs that began with the E-1 in 2003, and the Micro Four Thirds PEN and OM-D bodies that followed from 2009.

.orfImage Files

ORF at a glance#

Full name	Olympus Digital Camera Raw Image File
File extension	.orf
Category	Image Files
Developer	Olympus Corporation, now OM Digital Solutions
MIME types	image/x-olympus-orf
Compression	Varies from file to file
FileFlip support	FileFlip reads this format but does not write it

What a .orf file can hold#

These are the things a ORF file either supports or does not, and they are what decides whether a conversion keeps everything or quietly drops something.

Lossless compression	Yes
Embedded metadata	Yes
Colour profiles	Yes

Strengths and limitations of ORF#

What ORF does well

Four Thirds sensors measure about 17.3 by 13 mm, roughly a quarter the area of full frame, so an ORF is much smaller than a full-frame raw of the same generation
OM Workspace can hand raw development back to a connected camera over USB on the OM-1, OM-1 Mark II, OM-3 and several E-M1 bodies, so the result matches what that camera would have produced itself
The extension survived the sale of Olympus's camera business, so a 2005 Olympus file and a 2024 OM System file open in the same software

Where ORF falls short

The internal layout changed between camera generations, so a reader that handles one Olympus body can still fail on an ORF from another
Olympus never published an ORF specification, so every reader outside OM Workspace is reverse engineered
Third-party decoders trail new bodies, and LibRaw 0.22's supported camera list covers the OM-1, OM-1 Mark II and OM-5 but not the OM-3
No Olympus or OM System camera writes DNG, so a DNG-based archive always needs a conversion pass afterwards

ORF is what an Olympus or OM System camera writes when you shoot raw, so it is the file you keep if you want to redevelop the shot later rather than accept the camera's JPEG.

Convert ORF to JPEG when the picture has to be shared or printed, or to DNG when you would rather archive in a documented format than depend on reverse-engineered readers for a discontinued Olympus body.

How to open a .orf file#

A .orf file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts ORF into a format your machine already opens, and it does it in the browser tab rather than on a server.

Platform	Programs that open it
Windows	OM Workspace, Adobe Lightroom, Adobe Photoshop, Capture One, Corel PaintShop Pro, Corel AfterShot Pro
macOS	OM Workspace, Adobe Lightroom, Adobe Photoshop, Capture One, Photos, Preview
Linux	darktable, RawTherapee
iOS	Adobe Lightroom, Adobe Photoshop Express
Android	Adobe Lightroom, Adobe Photoshop Express
Web	FileFlip

ORF questions people ask#

What software opens ORF files?

OM Workspace, the manufacturer's own application and the successor to Olympus Workspace, opens ORF files, and so do Adobe Lightroom and Camera Raw, Adobe Photoshop, Capture One, and the open source darktable and RawTherapee. OM Workspace has one thing the others do not: on bodies like the OM-1, OM-1 Mark II, OM-3 and E-M1 Mark III it can send an ORF back to the camera over USB and let the camera's own processor develop it.

Are Olympus ORF files and OM System ORF files the same thing?

Yes. Olympus agreed in September 2020 to hand its imaging division to the investment fund Japan Industrial Partners, the transfer completed on 1 January 2021, and the new company was named OM Digital Solutions and began selling cameras under the OM System brand. The raw format did not change with the ownership, so an ORF from an OM System OM-1 and an ORF from an Olympus E-M1 are the same kind of file and the same software reads both.

Does converting ORF to DNG lose anything?

Converting an ORF file to DNG keeps the sensor data exactly as the camera recorded it, so image quality is unchanged and the picture is still fully editable afterwards. What can be lost is Olympus-specific metadata in the maker notes, along with any adjustments already stored by OM Workspace, since settings written by one company's software are rarely understood by another's. Adobe DNG Converter leaves your ORF files where they are rather than replacing them, so keeping both is an option.

Why do Olympus and OM System use ORF instead of DNG?

OM System keeps ORF for the same reason Canon, Nikon, Sony and Fujifilm keep their own raw formats: the manufacturer can record whatever a new sensor or a new feature needs without waiting for Adobe to revise the shared DNG specification, and its own software then reads that data with no translation. Olympus and OM System cameras have never offered DNG as an in-camera option, so converting is always a step you take afterwards.

Converting ORF files#

FileFlip does not write .orf files, so nothing on the site converts into this format. It works as a source only.

Every conversion runs inside your browser. The file is read from your disk, the work happens on your own machine, and nothing is uploaded. How FileFlip works names the engine behind each family and how to verify that for yourself.