Thank you for using Justanswer.
Adobe Photoshop does a good job.But it is not free.
For freeware i would recommend Irfan viewer
IT is able to read Canon, Nikon, Minolta, Olympus, Fuji, Kodak, Sony, Pentax (CRW/CR2, NEF, MRW, ORF, RAF, DCR, SRF, PEF, X3F) RAW formats, and "classical" RAW files
w/ irfan you can easily batch convert images using File->"Batch Conversion/Rename"...
very simple and effective... and for free
Hope this helps.