I am a Mac user running 10.6.5 and have installed Photoshop CS5. My downloaded ACR6.3 image files with DNG6.3 are showing, on enlargement, a nasty kind of mosaic pattern, similar to the reticulation effect with old B&W film. (JPEGs downloaded at the same time are OK). Both Ricoh GX200 & Lumix LX5 cameras show this effect.
Example shows an area of a 100% zoom of image: www.flickr.com/photos/rawmike/5282871896/
Has anyone got an explanation?