Suggestions: migrate to Yosemite.....upgrade to 8GB of memory....replace boot drive with an SSD Those will give you a real performance boast.
Raw conversion of camera files is handled by the OS, not the app itself (Aperture, iPhoto, Phots) Apple publishes the list of cameras that are supported by the specific OS releases and raw compatibly updates:
https://support.apple.com/en-us/HT203088
Supported by Digital Camera RAW Compatibility Update 6.04
Canon EOS 5DS
Canon EOS 5DS R
Canon EOS Rebel T6i / 750D / Kiss X8i
Canon EOS Rebel T6s / 760D / Kiss 8000D
Fujifilm X-A2
Hasselblad CFV-50c
Hasselblad H5D-50c
Leica C (Typ 112)
Nikon 1 S2
Nikon D7200
Olympus OM-D E-M5 Mark II**
Panasonic LUMIX CM1
Panasonic LUMIX DMC-GF7
Pentax MX-1