Póki co MS nie robił update codeców swoich i nie jest możliwe podgklądniecie RAW z Mk IV w explorer.
Sprawdź to coś, moze zadziała: FastPictureViewer Codec Pack: PSD, CR2, NEF, DNG RAW codecs (and more) for Windows 8.x Desktop, Windows 7, Windows Vista and XP

The FastPictureViewer Codec Pack adds fast thumbnail and preview support to Microsoft Windows for many image formats, including RAW formats from more than 580 digital cameras, Photoshop PSD, OpenEXR, TGA, DDS, HDR, Maya IFF, SGI RGB, JPEG 2000 and more! The Codec Pack is compatible with Windows 10 Desktop, Windows 8.x Desktop, Windows 7, Windows Vista and Windows XP SP3 and also creates thumbnails for Google SketchUp, Adobe InDesign, Adobe Illustrator, EPS and Adobe PDF-XMP.
Find all your images visually, directly in Windows Explorer just like JPEGs, without the need to launch any program!