I have an old Gossen Luna-Pro F meter and I am trying to decide if I need to replace it. I have tried metering a scene with different cameras and the Luna-Pro and comparing the readings but I can't seem to draw any conclusions. I need a meter when I shot my RB67 and I am under the impression that I will get more accurate readings with a hand held meter than a TTL camera meter???? Is there a method to test the Luna-Pro that is not so complicated that I need a degree in physics to use? I have been looking at the Gossen Digi-Pro F or the Sekonic L-308S but why spend the money if my old Luna-Pro is just as accurate? Maybe I just do not know how to use it correctly???