What is RAW?
RAW isn't a single format but a family of file formats that contain minimally processed data from digital camera or scanner image sensors. Unlike standard formats like JPEG, RAW files preserve all the data captured by the sensor, giving photographers maximum flexibility and quality for image editing. Each camera manufacturer typically has its own proprietary RAW format.
Key Features
The primary advantages of RAW formats include:
- Maximum data preservation: Captures all information from the camera sensor
- Higher bit depth: Typically 12-14 bits per channel versus JPEG's 8 bits
- Non-destructive editing: All processing can be altered later without quality loss
- Greater dynamic range: Preserve details in very bright and very dark areas
- Flexible white balance: Can be adjusted after shooting with no quality loss
- No compression artifacts: Data is either uncompressed or uses lossless compression
Common RAW Formats
Different camera manufacturers use their own RAW formats:
- .CR2/.CR3: Canon's RAW formats
- .NEF: Nikon's Electronic Format
- .ARW: Sony's Alpha RAW format
- .ORF: Olympus RAW Format
- .RAF: Fujifilm's RAW format
- .DNG: Adobe's Digital Negative format (an open standard)
When to Use RAW
RAW is ideal for:
- Professional photography where quality is paramount
- Difficult lighting conditions requiring exposure adjustments
- Shots that will undergo significant editing
- Situations where capturing maximum detail is critical
- Archival purposes when future editing might be needed
Limitations
Despite their advantages, RAW formats have several limitations:
- File size: Much larger than processed formats like JPEG
- Processing required: RAW files need to be processed before sharing or printing
- Software compatibility: Requires special software for viewing and editing
- Proprietary issues: Camera-specific formats may have limited support
- Not web-friendly: Cannot be used directly on websites
The RAW Workflow
Working with RAW files typically involves a specific workflow:
- Capture images in camera's RAW format
- Import to RAW processing software (Adobe Camera Raw, Lightroom, Capture One, etc.)
- Adjust exposure, white balance, contrast, etc.
- Export to standard formats like JPEG or TIFF for sharing or printing
- Archive original RAW files for future editing if needed
DNG: The Universal RAW Format
Adobe's Digital Negative (DNG) format was created to address the fragmentation of proprietary RAW formats. DNG provides an open standard that aims to ensure long-term accessibility of RAW images, regardless of whether camera-specific software continues to be supported. Many photographers convert their proprietary RAW files to DNG for archival purposes.
Conclusion
RAW formats represent the digital equivalent of a photographic negative. While they require more storage space and processing time than JPEGs, they offer unmatched quality and flexibility for serious photographers. As storage becomes cheaper and processing power increases, shooting in RAW has become standard practice for professionals and enthusiasts who want to extract the maximum quality from their digital cameras.