It works the same as a +4 close up filter, so the lens have to be at least 25cm (around that) from the subject in order to focus. It should cost around $100++ though I got it for $100 at mscolors last year. If you want to take the subject from a slightly further distance, u can consider attaching another telephoto convertor ontop of the close up filter but the magnification will be slightly lesser than using the close up filter alone.