A forgotten solution: Why this strange 1975 zoom lens is so sharp

For a few years now, I’ve had in my collection one very strange lens. I bought it primarily for it’s value as a collectible so, up until now, I haven’t really spent much time playing with it. Made in 1975, this manual focus Minolta MC Rokkor-X 40-80mm F2.8 lens is one strange puppy. When it was first introduced, no other zoom lens could top its image quality and it really didn’t have much competition until more recent years. This is largely due to its very unique Gearbox design that...