If you want to open Canon photographs, you need to use a RAW image viewer instead of common ones. It would be better if you can view RAW images in EXIF mode. Because it is a good way to get detail information of professional photographs.
Firstly, let's talk about RAW photo viewer for Mac. WidsMob Viewer is one of the best RAW viewer to handle large amount of RAW files with 5X speed. You can use the Windows-like image viewer to open all RAW images with left or right arrows directly. Let's see the supported 35 RAW formats here.
(RAF / 3FR / RAW / MOS / MRW / RAF / PEF / ORF / NEF / ERF / RWL / EXR / SGI / DNG / CR2 / CRW / ARW / SRF / X3F / KDC / SR2 / ARI / R3D / MDC / FFF / MEF / RW2 / RWZ / PEF)
Then how about the RAW image viewer for Windows? You can choose from FastStone Image Viewer, XnView and other choices here.