Hello Mel, Well, both are wery good glasses I would say get the F4, pricewise. Remember that usually the best setting for your lens will be around f8. I usually use the wider openings for focusing and composing, but I step down when printing, Anyway you will not see an appreciable difference between f2,8 and f4, it will be what, tenth of seconds or seconds when printing, depending on the begative density, contrats, paper etc. Print on Pierlucio
