LuttieRAW File Formats Explained: CR2, ARW, NEF, DNG and More
What's the difference between CR2, ARW, NEF, and DNG? This guide breaks down every major RAW format, which cameras use them, and how to work with them.
When your camera shoots RAW, it saves the unprocessed sensor data directly to your card — no compression, no in-camera colour processing, no sharpening. What you get is the full information from the sensor, ready to be processed exactly how you want.
The catch is that every camera manufacturer has their own RAW format. CR2 is Canon's. ARW is Sony's. NEF is Nikon's. DNG is Adobe's attempt at a universal standard. They all contain essentially the same kind of data, but they're structured differently and require different decoders to read.
Here's what you need to know about each one.
CR2 and CR3 — Canon
CR2 (Canon Raw 2) has been Canon's primary RAW format since the mid-2000s. It's based on TIFF and is widely supported across editing software. If you're shooting with a Canon DSLR from the last 15 years, your files are almost certainly CR2.
CR3 is Canon's newer format, introduced with the mirrorless EOS R series. It uses a more efficient compression method and is gradually replacing CR2, though support across third-party software took time to catch up.
Both formats retain full sensor data including colour profiles, white balance metadata, and lens correction information.
ARW — Sony
ARW (Sony Alpha Raw) is used across Sony's full Alpha lineup — from APS-C bodies like the A6700 to full-frame cameras like the A7R V. Sony has iterated on the format over the years, and newer ARW files from recent bodies include more compression options and higher bit depth.
ARW files tend to be excellent for shadow recovery — Sony's sensors have strong dynamic range, and the RAW format preserves all of it.
NEF and NRW — Nikon
NEF (Nikon Electronic Format) is Nikon's RAW format, used across DSLRs and Z-series mirrorless cameras. Nikon offers several compression options within NEF — lossless compressed, lossy compressed, and uncompressed — all under the same .nef extension.
NRW is a simpler RAW format used in Nikon's compact cameras. It contains less data than NEF and is less commonly encountered.
DNG — Adobe
DNG (Digital Negative) is Adobe's open, universal RAW format. It was created specifically to address the fragmentation problem — instead of every manufacturer using a different format, DNG provides a common container that any software can support.
Some cameras shoot DNG natively, including most Leica cameras and many Android phones with RAW capability (Pixel, some Samsung). Other cameras output their proprietary format, and you can convert to DNG using Adobe DNG Converter if you want a more universally compatible archive format.
DNG has a few practical advantages:
- Smaller file sizes — DNG files are often 15–20% smaller than the equivalent proprietary RAW
- Embedded previews — DNG can embed a full-resolution JPEG preview
- Long-term compatibility — as an open standard, DNG is more likely to remain readable in 20 years than a proprietary format that could be discontinued
The main downside is that converting to DNG adds a step to your workflow, and some photographers prefer to keep original files in their native format.
RAF — Fujifilm
RAF (Raw Fujifilm) is Fujifilm's RAW format, used across the X-series and GFX medium format systems. RAF files are notable because Fujifilm's X-Trans sensor has a non-standard colour filter array — instead of the standard Bayer pattern used by almost every other camera, X-Trans uses a more complex 6×6 pattern.
This means RAF demosaicing (the process of converting raw sensor data to a full-colour image) is more computationally intensive, and some software handles it better than others.
Other Formats
| Format | Brand | Notes |
|---|---|---|
| RW2 | Panasonic | Used in Lumix cameras |
| ORF | Olympus / OM System | Standard Bayer sensor layout |
| PEF | Pentax | Used in K-series DSLRs |
| SRF, SR2 | Sony | Older Sony formats |
| 3FR | Hasselblad | Medium format |
| IIQ | Phase One | Medium format |
Which Format Should You Shoot?
If your camera gives you a choice, the answer depends on your priorities:
Shoot your camera's native format if you want the fastest workflow with your manufacturer's own software (Canon Digital Photo Professional, Sony Imaging Edge, Nikon NX Studio). Native formats are always fully supported by first-party tools.
Convert to DNG if long-term archiving is a priority, or if you work across multiple systems and want a single consistent format.
Keep both if storage isn't a concern — shoot native RAW and convert a DNG copy for archival.
Working With RAW Files
The good news is that modern tools are catching up to the fragmentation. Most major editing applications support all the common formats, and browser-based tools are starting to as well.
Luttie's editor supports CR2, CR3, ARW, NEF, DNG, RAF, RW2, ORF, and PEF — you can drop any of these directly into the browser, apply a colour grade or LUT, and export without installing anything. RAW support is available on Pro accounts.
Understanding your RAW format matters most when something goes wrong — when software doesn't recognise a new camera body, or when you're archiving files for the long term. In day-to-day shooting, the differences between formats are minor enough that your choice of camera and lens will always matter more.