Okay, just bought a Canon EF 300mm f/2.8L IS II USM Image Stabilizer. Never had a camera with a drop in filter before. Half the reason (or more?) I bought filters before was to protect the lens. Is a good haze filter (or other filters) good for drop-in on this lens, or is it just more glass to distort the image and decrease transmission? Can you just do as well in post-processing in DxO? Or, do the benefits of drop-in filters outweigh the negatives? Opinions appreciated. Thx.