I've been searching the internet for a proper focus screen for my 550D. I know it's not supported by Canon but I also it's possible and want to take advantage of it I've been looking for a dual 45° screen with focus indicator etchings, but every screen I found had either one or the other, but never both. Other than this overpriced one. I'm not eager to spend $40+ on a focusing screen... Should I just opt for the 180° screen with indicators, 45° with no indicators, or any other suggestions? Thanks!