Here's a neat little trick you can use when photoreading with material contained in a any binder of any sort. This is especially true of Photoreader's who are new and sometime's have trouble maintaing the photo focus state.
Take a marker of some sort, color of your choice, but darker colors work best for me. Make a little dot mark on the middle binder ring at the center. Now when Photo focusing look at the dot, when two appear, your in perfect photo focus state!