This is the basic program to work with .PEF extension

FastStone Image ViewerFastStone PEF File

FastStone Image Viewer provides you with a practical and alternative way to enjoy your photo collections - you can view each photo in full-screen mode with high quality and in full detail. However, the program does much more than its name suggests, as it can also edit and convert your images in batches, compare them, create stunning slideshows, print your images with full control, and more... (more) The program works with the following extensions: bmp, gif, jpg, png, psd, wmf, jpeg, nef, orf, pcx, jpe, pef, raf, srf, arw, tif, tga, cr2, crw, dng, mrw and tiff

.PEF extension is also supported by the following programs:

	PaintShop Photo ProPaint Shop Pro Studio Image
	Photo-Editing software for amateur photographers and profesionals.

	PENTAX Digital Camera UtilityPENTAX Raw File

	FastStone MaxViewMySQL Tools for
	Enjoy your photos in full detail and edit them in various practical ways.

	MAGIX Photo Managerpef Raw-Image
	Photo Manager lets you present your photos and videos impressively.

	Zoner Photo StudioRAW bitmap image
	ZPS X – intuitive, lightning-fast software for your photos.

	FiregraphicRAW Image
	Firegraphic is a powerful tool for organizing and editing photos.

	ACDSeeACDSee 8.0 PEF Image
	Organize, edit, and share your photos with ease.

	Smart Pix ManagerSmart Pix Image
	Smart Pix Manager - management and viewing of all types of media files.

	Corel Paint Shop ProPaint Shop Pro 9 Image
	Corel Paint Shop Pro is a complete graphics package.

	Helicon FilterMySQL Tools for
	Helicon Filter is a program for image editing with task oriented interface.

	PrintingPressPrintingPress Exported File
	The best software for printing invitations and announcements at home.

	Free Download ManagerMySQL Tools for
	Simple and highly efficient tool to manage and schedule all your downloads.

	UFRawUFRaw photo
	UFRaw (Unidentified Flying Raw) is an editor for raw images.

	ArcSoft PhotoStudio DarkroomPhotoStudio Darkroom PEF Image
	PhotoStudio Darkroom lets you edit and apply enhancements to your digital photos.