I've several manual focus lens and focusing task with my Canon 550D is near a guess. So I have a big collection of out-of-focus photos. Canon states that original 550D screen can not be replaced by a focusing one. In fact it is not the easiest thing to do. After a long waiting, at last the focusing screen arrived from China for US$ 15.00. The instructions that came with it, are almost useless as translation is near very bad. So I recommend to check on internet for Katz Eye screens change instructions. If you are going to do it, be patient and pay attention to the original screen orientation, as you need it to install the new one. At the end the result is excellent. Now manual focus is easy as it was on analogue SLR cameras.
