I am a newbie to the mf lenses for my D200 and D70 DSLRS. Just bought a 200 1:4 ai lens and am difficulty focusing. Also just acquired a 28 mm 1:2.8 ai-s lens and the focusing was a breeze. Any learning curve observations will be greatly appreciated. Is the problem with my vision (being 68 yrs with corrected 20./20); my technique, the D200's focus screen???? I am reluctant to go the Katz Eye route if the only rationalization is for using a MF lens. Your thoughts...and thank you!