Bought one of these five years ago to shoot a wedding reception. It worked fine for that - all flash, indoors, 10-20 foot range, SB-28 on an F5. Since then, I've tried to use it in other applications - b&W landscape, street shooting etc. - and have been generally disappointed with the sharpness. Is there a trick - certain f stop - where it works available light or is it just a dog like the old 43-86?