Roger Cicala: the difference between sample variation and a 'bad copy' (Part 2)

I compare a lot of lenses. They aren't all exactly the same. In today's article we'll look at variation versus bad copies a bit differently to last time. Plus, I'll explain how people get three 'bad copies' of a lens in a row. Variation versus bad copy frequency Imatest type graphs are easier to visualize so I'm going to use those today. These graphs allow us to visualize center resolution (toward the top on the y-axis of the graph) and overall resolution (toward the right on the x-axis), with i...