A DNG file, short for Digital Negative, is an open raw image format created by Adobe. You do not have to convert your raw files to DNG, but it can make sense if you want one self-contained file per photo or a format that is documented publicly. Many photographers leave their originals as they are.
What a DNG File Is
Camera makers each use their own raw formats, and those formats can change with each new model. DNG was designed as a common format with a published specification. It holds the same unprocessed sensor data as a raw file, plus metadata such as camera settings and, if you wish, your edits.
Some cameras and phones record DNG directly, so in that case there is nothing to convert.
Possible Benefits of Converting
- Embedded metadata: edit settings can be stored inside the file, so no separate sidecar file is needed.
- Open specification: the format is publicly documented, which some people value for long term access.
- File size: lossless compression can make files smaller than some maker formats.
- Verification: DNG files include checksum information that can help detect corruption.
Possible Drawbacks
- Conversion takes time and extra disk space while you keep the originals.
- Some maker specific data may not be carried across unless you embed the original raw file, which makes the DNG larger.
- Some maker software cannot read DNG, or may treat it differently.
- Rewriting a file each time you change metadata means more writes to your drives and more to back up.
| Question | Leans toward converting | Leans toward keeping originals |
|---|---|---|
| Storage | Space is tight | Plenty of space |
| Software | Everything is Adobe based | Maker software is used |
| Workflow | Want fewer sidecar files | Happy with sidecars |
How to Convert in Lightroom
- In the Import window, choose Copy as DNG at the top to convert while importing.
- Or select photos already in your library and choose Library, then Convert Photos to DNG.
- Decide whether to embed the original raw file. Embedding keeps a recoverable copy but increases size.
- Keep your original raw files until you have confirmed the converted files open correctly.
FAQ
Does DNG change my image quality?
The conversion keeps the raw sensor data without loss, so image quality is unchanged. Confirm the details on Adobe’s page for your camera.
Can I turn a DNG back into my camera’s raw file?
Only if you embedded the original when converting. Otherwise the conversion is one way.
The Short Version
DNG is an open raw format that bundles image data and metadata in one file. Converting is optional, and it suits people who want fewer sidecar files and use Adobe tools. If you are unsure, keep your original raw files, or embed them inside the DNG.
