I thought I'd take a look at the main differences between Lightroom 2, 3 and 4. Below is a comparison of all the features between the three versions.
via: Buying guide | Adobe Photoshop Lightroom 4
Lightroom Feature | 2 | 3 | 4 |
Location-based photo organization | * | ||
Importing libraries from other software | * | ||
Extended video support | * | ||
Basic support for video files | * | * | |
Improved watermarking | * | * | |
Cross-platform 64-bit support | * | * | |
Multiple monitor support | * | * | * |
Offline photo management | * | * | * |
Batch application of Develop settings | * | * | * |
Adobe Photoshop integration | * | * | * |
Develop presets | * | * | * |
Tools to manage and refine many images at once | * | * | * |
Comprehensive image management | * | * | * |
Multiple viewing options | * | * | * |
DNG conversion | * | * | * |
Single or group metadata stamping | * | * | * |
File renaming | * | * | * |
Advanced search and sort | * | * | * |
Simple, customized keywording | * | * | * |
IPTC/EXIF/XMP metadata support | * | * | * |
Timesaving presets for import/export | * | * | * |
Metadata stamp on import | * | * | * |
Highlight and shadow recovery | * | ||
White balance brush | * | ||
Additional adjustment brush options | * | ||
Advanced noise reduction | * | * | |
Film grain simulation | * | * | |
Lens correction | * | * | |
Perspective correction | * | * | |
Selective editing brush | * | * | |
Nondestructive environment | * | * | * |
Superior image processing | * | * | * |
Tracking of editing adjustments | * | * | * |
Before-and-after comparison | * | * | * |
Advanced black-and-white conversion | * | * | * |
Simplified tone curve tools | * | * | * |
Advanced hue, saturation, and luminance editing | * | * | * |
Intelligent sharpening | * | * | * |
Dust-busting | * | * | * |
Red-eye removal | * | * | * |
Photo book creation | * | ||
Video publishing | * | ||
Soft-proofing | * | ||
Direct email support | * | ||
Enhanced online sharing integration | * | * | |
Improved customizable print packages | * | * | |
Portable, easy-to-share video slide shows | * | * | |
Flexible online publishing directly from Lightroom | * | * | |
Integration with Flickr, a Yahoo! service | * | * | |
HTML or Adobe Flash Player compatible web gallery output | * | * | * |
One-click publishing to your website | * | * | * |
via: Buying guide | Adobe Photoshop Lightroom 4