Understanding RAW Camera Formats — CR2, NEF, ARW, DNG Explained

July 16, 2026

If you shoot with a DSLR or mirrorless camera, you've definitely seen RAW as an option in the quality settings menu. Camera manuals do a terrible job explaining what RAW actually is or why you'd want to use it. The short answer is that RAW files contain every bit of data your camera sensor captured, with no processing applied. That gives you maximum flexibility when editing, but it also means you can't share RAW files directly. They need to be converted first.

What Is a RAW File?

A RAW file isn't an image in the traditional sense. It's a container that holds the raw sensor data from your camera's image sensor, along with metadata about camera settings, lens, white balance, and more. Unlike JPEG, which applies sharpening, noise reduction, and color correction inside the camera, a RAW file stores the unprocessed data. Every RAW file also contains an embedded JPEG preview — that's what you see on your camera's LCD screen.

The downside is that RAW files are massive. A 24-megapixel camera produces RAW files around 25 to 35 MB each. The upside is the editing headroom. You can adjust exposure by several stops without introducing artifacts, fix white balance after the fact, and recover highlight and shadow detail that would be completely lost in a JPEG.

Manufacturer RAW Formats

Every camera manufacturer has its own RAW format. They all serve the same purpose, but they're not interchangeable. Here are the most common ones:

Embedded JPEG Previews

Every RAW file includes a JPEG preview image embedded in its metadata. This preview lets you view RAW files on your camera screen and in file explorers without decoding the full raw data. The preview is typically 1600 x 1200 pixels for standard cameras, though newer models include full-resolution previews. When you use a browser-based RAW to JPG converter that claims to work without decoding the sensor data, it's often just extracting this embedded preview and saving it as a standalone JPEG.

The embedded preview isn't the same as a properly converted RAW file. The preview has already been processed by the camera with its default settings applied. If you want true control over white balance, sharpening, and tone curve, you need software that decodes the actual sensor data — not just pulls the thumbnail.

Why Convert RAW to JPG?

RAW files aren't meant for sharing. You can't email a 30 MB NEF file to a client, and Instagram won't accept CR2 uploads. JPG is the universal sharing format. Converting to JPG shrinks the file size dramatically. A 30 MB RAW file might become a 3 MB JPG at high quality. The trade-off is that JPG uses lossy compression and discards data that can't be recovered.

There are two approaches to RAW to JPG conversion. First, you can use a desktop editor like Lightroom or Capture One, which gives you full control over the process. Second, you can use a quick online tool that extracts the embedded JPEG or does a basic decode. The online approach is faster and requires zero installation, but you sacrifice fine control over the output.

Converting RAW to JPG in the Browser

Browser-based RAW conversion works by reading the RAW file's structure using JavaScript libraries. The file is loaded via a file input element, and the browser reads its contents into memory as an ArrayBuffer. A JavaScript decoder then parses the RAW format's binary structure, identifies the sensor data and the embedded preview, and decodes the pixels. The resulting image data is drawn onto a canvas element, which can then export a JPEG blob.

The tricky part is that each RAW format has a different binary layout. CR2 files use a TIFF-based container with Canon-specific tags. NEF files follow a similar structure but with Nikon's own tag definitions. ARW files changed their internal structure between Sony's older and newer cameras. A complete decoder needs to handle all these variations. Tools like ConvertPivot's RAW to JPG converter handle the most common formats by extracting the embedded full-size JPEG preview, which works across almost all cameras without needing to decode the raw sensor data itself.

DNG: The Universal RAW Alternative

Adobe developed the DNG (Digital Negative) format as an open alternative to proprietary RAW formats. Any manufacturer can use DNG without paying licensing fees. Leica actually uses DNG natively. Many other cameras can output DNG with a firmware update. Adobe also offers a free DNG Converter that turns proprietary RAW files into DNG.

The big advantage of DNG is long-term compatibility. A proprietary RAW format might become unreadable if the manufacturer stops supporting it. DNG is an open standard documented by Adobe, so any software developer can implement it. The downside is that DNG files aren't universally supported by cameras themselves. Most cameras still write their own proprietary format. You have to convert to DNG on your computer.

Final Thoughts

RAW formats exist to preserve every bit of data your camera sensor can capture. They're not image files you can share directly. Each manufacturer has its own flavor with different compression, bit depth, and metadata structures. DNG sits in the middle as an open alternative that prioritizes long-term accessibility. For quick sharing, converting RAW to JPG is the pragmatic choice. For serious editing, keep the RAW originals and process them in dedicated software.