The problem comes from the filter glass: The 67mm filter has a special formula. But I dont have any red corners with my 21 mm and 24 mm, nor my 28 mm or 35 mm lenses. So, please, leave the M8 alone. The problem on the M9 is a different problem. And I won't buy a M8 ...
It’s utter garbage unless youonlyplan to cut acrylic or really need it for a trade show where there will be no window or something. The filter is overpriced and inefficient. It fills up super fast (we are talking a week or two for many users) and the replacement filters are $250. A...