Hi, I recently bought a used Rokinon 500mm f6.3 mirror lens for my Canon XSI to play around with. It was good price and i'm having a good time with it. I have a chance to buy a 95mm linear polarizer for it. Since the lens is manual focus will it be okay on my camera as long as i don't expect it to try and auto focus? Some things i've read say no the camera will give erroneous results. I'm just not sure if it will be okay for my purpose. Any help would be appreciated.