Im really new to dslrs and this is my first. I hae the normal 18-55mm lense that came with it, butI also have a Tamrn Pentax fit 80-210mm macro lense. I attatched it all fine, but now when I try to shoot the F keeps flashing and I cannot seem to fix it. Im sorry I sound so stupid, but i'm just trying to learn. Anyone know how to help?