ARW File Format (.arw)

An ARW file stores raw sensor data in Sony's current TIFF-based raw format, introduced in 2006 with the Alpha DSLR-A100 and used by every Alpha DSLR, SLT and mirrorless camera Sony has released since, replacing the short-lived SR2 format Sony had used on cameras like the Cyber-shot DSC-R1.

.arwImage Files

ARW at a glance#

Full name	Sony Alpha Raw Image Format
File extension	.arw
Category	Image Files
Developer	Sony Corporation
First released	2006
MIME types	image/x-sony-arw
Compression	Varies from file to file
FileFlip support	FileFlip reads this format but does not write it

What a .arw file can hold#

These are the things a ARW 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 ARW#

What ARW does well

One format has covered every Sony Alpha DSLR, SLT and mirrorless camera for nearly two decades, so support in raw software is broad and mature
Offers uncompressed, lossless-compressed and lossy-compressed saving options, so a photographer can trade file size against fidelity per shot

Where ARW falls short

Sony's lossy compression mode uses an 11+7 bit delta scheme that can visibly posterize skies and other smooth gradients under some conditions
Undocumented maker-note fields mean third-party raw processors sometimes lag behind Sony's own Imaging Edge software on a brand-new camera body

ARW is what every current Sony Alpha or mirrorless camera writes automatically, so choosing between uncompressed and compressed ARW in the camera's menu is the only real decision.

Convert ARW to JPEG for sharing and printing, or to DNG when a particular piece of software hasn't yet added support for a brand-new Sony camera body.

How to open a .arw file#

A .arw file opens in the programs below, grouped by the platform you are on. If you would rather not install anything, FileFlip converts ARW 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	Sony Imaging Edge Desktop, Adobe Photoshop, Adobe Lightroom, Capture One
macOS	Sony Imaging Edge Desktop, Adobe Photoshop, Adobe Lightroom, Capture One, Preview
Linux	darktable, RawTherapee
iOS	Adobe Lightroom
Android	Adobe Lightroom
Web	FileFlip

ARW questions people ask#

What software opens ARW files?

Sony's own Imaging Edge Desktop opens ARW files, as do Adobe Photoshop, Lightroom and Camera Raw, Capture One, and open-source tools like darktable and RawTherapee. ARW is Sony's current raw format, so support is broad across both paid and free raw processors.

Does converting ARW to DNG lose quality?

No, converting an ARW file to DNG keeps the same sensor data, since DNG conversion doesn't re-render the image. A small amount of Sony-specific metadata can be lost in the conversion, but not image quality.

Should I shoot compressed or uncompressed ARW?

Uncompressed ARW avoids Sony's lossy 11+7 bit delta compression, which can visibly posterize smooth gradients like skies under some conditions, at the cost of a larger file. Sony's lossless-compressed option is a middle ground that shrinks the file without that risk.

Which Sony camera first used ARW?

The Alpha DSLR-A100, Sony's first Alpha-branded DSLR, introduced ARW in 2006, replacing the SR2 format Sony had used on earlier cameras like the Cyber-shot DSC-R1. Every Alpha DSLR, SLT and mirrorless camera Sony has released since has written ARW, making it the only raw format across the current Alpha and RX lines.

Why does Sony use ARW instead of DNG?

Sony uses ARW, like other camera makers use their own raw formats, so it can add camera-specific metadata and features without waiting on Adobe to update a shared DNG specification. Sony's cameras don't write DNG in-camera; converting to DNG is always a separate step done afterward.

Converting ARW files#

FileFlip does not write .arw 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.