What Is an RW2 File? Panasonic's RAW Format, Explained
An RW2 file is Panasonic's Lumix RAW format — what a GH, G or S-series body writes when you shoot RAW, and what the advanced LX and FZ compacts write too. It is not a finished picture. It holds the reading from every photosite on the sensor at the instant of exposure, plus the camera's metadata and embedded JPEG previews, in a single .RW2 file built on the same TIFF foundation as most camera RAW formats. That makes it your digital negative: the whole photograph, before any decisions about how it should look were locked in.
If you shoot a GH body for video, the same idea applies to your stills: the footage may be the job, but the RW2 is the negative you'll be glad you kept. Here's what's inside one, and how to work with it on a Mac.
RW2 at a glance
| Full name | Panasonic Lumix RAW |
|---|---|
| Extension | .RW2 |
| Introduced | 2008, on the LX3 compact and the G1; the extension on every RAW-shooting Lumix since |
| Written by | Lumix mirrorless bodies (GH, G and S full-frame lines) and advanced compacts (LX, FZ) |
| What it holds | Unprocessed 12- or 14-bit sensor data (depending on body), EXIF metadata, your Photo Style setting, the lens-correction profile, embedded JPEG previews |
| Structure | Built on TIFF, like most camera RAW formats |
| Relatives | The earliest Lumix bodies wrote a bare .raw extension; Leica-branded twins of Lumix cameras write the same data as .RWL |
| Typical size | Roughly 20–45 MB on 20–47 MP bodies |
| Opens with | macOS Preview and Photos, and RAW editors such as RevelRaw, Lightroom or Capture One |
What's actually inside an RW2 file
A camera sensor doesn't record a picture. Each photosite records how much light hit it through a single-color filter — red, green or blue — arranged in a mosaic. An RW2 file stores those readings as they came off the sensor:
- The mosaic sensor data. One brightness value per photosite, at 12- or 14-bit precision depending on the body. No white balance, no sharpening, no Photo Style has been applied yet — turning the mosaic into a viewable photograph is the job of your RAW editor.
- Metadata. Camera body, lens, exposure settings, and the Photo Style you had dialed in. Editors read this to know how to interpret the data; nothing in it is baked into the pixels.
- The lens-correction profile. Panasonic designs Micro Four Thirds glass and its compact zooms to be finished in software: the projection straight off the lens carries distortion and vignetting that the profile stored in the RW2 removes. RAW editors apply it before you ever see the image, which means the file carries part of the optical formula — open one in software that skips the profile and a wide shot shows bowed horizons the lens was never meant to deliver uncorrected.
- Embedded JPEG previews. The camera develops previews with its own processing and tucks them inside the RW2. That's what you see on the camera's screen and in Finder thumbnails — which is why a RAW file can look one way as a thumbnail and another once an editor opens the real data.
One sensor, three badges
Panasonic's RAW has worn three names over the years. The earliest Lumix bodies wrote files with a bare .raw extension — no brand initials at all — before .RW2 arrived and settled in for good. And Leica-branded twins of Lumix cameras record the same data under the .RWL extension — same negative, different badge on the front plate. In practice the history costs you nothing: any mirrorless-era Lumix writes RW2, and that's the extension everything below is about. (A fourth extension, .HSP from the HLG Photo mode on some newer bodies, is a separate format — our guide to opening RW2 files covers what reads it.)
What matters more than the name is what the format holds. Panasonic's Photo Styles get baked into JPEGs, but an RW2 only records your choice in metadata and keeps the sensor data underneath. Shoot a moody monochrome Photo Style today, and the color is still sitting in the file if you want it back next year.
Which cameras write RW2? Every Lumix since 2008
The extension dates to 2008, and it debuted on two very different cameras: the LX3, an enthusiast compact, and the G1 — the first mirrorless interchangeable-lens camera ever sold. Panasonic has stayed with it ever since. Eighteen years of bodies later, an S5 II, S9, G9 II or GH7 writes the same .RW2 a G1 did, with no successor format and no version suffixes along the way.
That stability pays off when your Lumix is older. A GH2 from 2010 or a G3 from 2011 writes RW2 like any current body, and today's software still opens those files — the macOS decoder and the major RAW editors all carry the back catalog. Pull a decade-old card from a drawer and the G3's 16-megapixel files take modern noise handling and color work that didn't exist when the camera shipped.
The format also reaches well past the interchangeable-lens lines. Panasonic's long-zoom FZ bridge cameras write RW2 whenever they shoot RAW, and so do the pocketable enthusiast models — the LX series and the RAW-capable travel zooms. A used FZ1000 or LX100 produces the same kind of negative an S-series body does, just from a smaller sensor. Every Lumix guide on this site is gathered on the Panasonic hub.
One footnote for anyone searching "RW2 file from my DSLR": strictly, no DSLR writes RW2. Panasonic built two true DSLRs, the L1 and L10, and both predate the format — they belong to the bare-.raw era. The G and GH bodies that replaced them in 2008 kept the DSLR silhouette, viewfinder hump and all, but there's no mirror inside. If your "Panasonic DSLR" fills a card with .RW2 files, it's one of those.
How big is an RW2 file?
Two numbers set the size: how many photosites the sensor has, and whether each reading is stored at 12 or 14 bits. Megapixels times bit depth, divided by eight, puts a ceiling on the file in megabytes, and Panasonic's packing brings it in somewhat under that. The subject in front of the lens plays no part.
| Sensor generation | Example bodies | Typical RW2 |
|---|---|---|
| 12 MP Micro Four Thirds | G1, GH1, GF1 | Roughly 15 MB |
| 16 MP Micro Four Thirds | GH2, G3, GX85 | Roughly 20 MB |
| 20 MP Micro Four Thirds | GH5, G9, GX9 | Mid-20s MB |
| 25 MP Micro Four Thirds | G9 II, GH7 | Toward 30 MB |
| 24 MP full frame | S1, S5, S5 II, S9 | Around 30 MB |
| 44–47 MP full frame | S1R, S1R II | Toward the mid-40s MB |
Within one body, the sizes barely move. Panasonic's RAW menu offers no compression levels and no quality steps — RAW is a single setting — so a frame of empty night sky and a frame of market clutter land within a megabyte of each other. Nikon shooters budget around a four-option compression menu (the NEF story covers it); a Lumix shooter multiplies frames by one number and knows what the shoot weighs.
The trade: with no compact option, an RW2 can't be made smaller in camera, only converted to something else afterwards. And between a 12-bit body and a 14-bit one at the same resolution, expect the deeper file to run heavier — the extra bits are where the added tonal headroom lives.
How to open RW2 files on a Mac
macOS ships with RAW support for most Lumix bodies, so the basics are already on your Mac: Preview opens RW2 files with a double-click, and Photos imports them. Two caveats. First, files from a just-released camera can fail to open until Apple ships a RAW update for that body — the file isn't broken; your software just hasn't met that camera yet. Second, Preview only shows you a develop of the RAW; it isn't an editor.
To actually develop the file — choose your own white balance, recover highlights, work the color — you need a RAW editor. RevelRaw is built around Sony Alpha, but it opens Panasonic RW2 files all the same — drag one in or pick it from File > Open, and AI scene detection ranks 40+ presets against your photo, with the standard fine-tune controls on top. Everything runs on your Mac; no file ever leaves it. The big subscriptions — Lightroom, Capture One — read RW2 as well.
How to convert RW2 to JPEG
For a quick conversion with no editing, Preview can do it: open the RW2, then File > Export, choose JPEG, and set the quality. For a conversion that's actually developed — your exposure, your color — open the file in a RAW editor and export. RevelRaw exports JPEG, PNG, TIFF and HEIF, with platform presets for Instagram, print and web. Either way, keep the RW2 afterwards: it's the negative, and every JPEG is just one interpretation of it.
FAQ
What RAW file type does the Panasonic Lumix G3 use?
RW2 — the same extension every Lumix has written since 2008. The G3's 16-megapixel files run around 20 MB and open in current macOS and in RAW editors such as RevelRaw without any special handling, so a card from one is still perfectly usable today.
Do DSLR cameras write RW2 files?
Strictly, no. Panasonic built two true DSLRs, the L1 and L10, and both predate RW2 — they wrote a bare .raw extension. Every RW2 comes from a mirrorless Lumix or an FZ or LX compact; the G and GH bodies just kept the DSLR silhouette when they dropped the mirror.
Are RW2 and Leica RWL files the same?
Effectively, yes. Leica-branded twins of Lumix cameras record the same image data under the .RWL extension. Different badge, same negative.
How do I open an RW2 file on a Mac?
Double-click it: Preview handles files from most Lumix bodies. Files from a just-released camera may need to wait for a macOS RAW update. To develop rather than just view the file, use a RAW editor such as RevelRaw.
Is RW2 12-bit or 14-bit?
Depends on the body — some record 12-bit, others 14-bit. Either way it holds far more tonal latitude than a JPEG, which is what makes highlight and shadow work possible later.
Can RevelRaw open RW2 files?
Yes. Drag an RW2 in and it opens like any other RAW — presets, scene detection and fine-tune controls all work. Exports go out as JPEG, PNG, TIFF or HEIF.
See what's really in your RW2 files. Download RevelRaw, drop one in, and watch it ranked against 40+ presets in seconds — with one full-quality export on the house. Get it on the Mac App Store.
Related reading: Panasonic RAW editing on a Mac · How to open RW2 files on a Mac · All RAW formats RevelRaw opens · RAF, Fujifilm's RAW · ORF, the Olympus and OM System RAW · What is an ARW file? · What is a NEF file? · What is a CR2 file?