Why won't Photos allow me to open/view RAW images?
I am shooting with a Nikon D810 and when I upload pictures to Photos it will not allow me to open/view the RAW files when selecting them. Like if I am viewing the thumbnail images I can see the picture but when I select it to open/enlarge it shows a gray card image with "!" Please help.
MacBook Pro, OS X Yosemite (10.10.4)