Hello, I have a couple of questions about lenses. I inherited 2 AF lenses from my dad and I have 3 of my own (1 standard kit lens and 2 prime lenses) as listed. I own a Sony Alpha. Minolta AF Lenses: 35-70mm f/3.5-4.5 70-210mm f/4.5-5.6 (Zoom) Minolta Prime Lenses: 50mm f/1.7 28mm f/2.8 Sony Lens: 18-70mm f/3.5-5.6 My question is about my prime lens (50mm f/1.7) What is the window telling me? The max/min aperture is 1.7/22. What does that mean? Thanks in advance.