Let me introduce you Minolta Lenses Classification Guide – as a simple and usable diagram for SR lenses (Auto-Rokkors, MC, MD, Celtic, etc.)
Minolta produced a lot of lenses in the life period of SR-mount (manual SLR lenses) and as many other companies didn’t care about a clear classification. For example – there were existed about fifteen lenses 28/2.8: one Auto Rokkor, five MC Rokkors, maybe one MC Celtic, seven MD Rokkor, and two MD. Most of these lenses are not the same by IQ and characteristics. Any owner has enough big chance to make a mistake with the determination of what exactly is the lens. And it’s OK. Not many people in the whole world are able to sort out with any Minolta SR lens (less than ten?).