A separate Smart Previews.lrdata file contains lossy DNG-encoded copies (typically ~1-2 MP). Key uses:
💡 If your thumbnails look different the moment you import them, it’s because Lightroom is replacing the camera's built-in JPEG preview with its own Raw rendering. You can change this by adjusting the "Raw Defaults" in the Preferences menu.
The .CR3 format is more efficient. It allows for smaller file sizes with the same quality, and it introduced a new feature called (Canon Log) which captures an incredibly flat image specifically for high-end color grading, preserving every scrap of dynamic range.
Based on Lightroom’s architecture:
If you have just imported a card full of .CR2 or .CR3 files into Lightroom, you might notice something immediately frustrating: they look flat, dull, and perhaps a little soft. You might wonder if your expensive lens is broken or if your camera settings were wrong.
To accelerate browsing, Lightroom generates previews stored in a folder with the .lrdata extension (e.g., Catalog Previews.lrdata ). Types of previews:
The .lrdata folder is a package (on macOS) or folder (on Windows) that can be rebuilt or deleted without affecting the original images or catalog edits.
If you are seeing the "The file is not recognized by the raw format support in Lightroom" error, follow these steps: 1. Update Adobe Camera Raw