Selecting lenses for machine vision

I think most machine vision users will confess to being baffled by the business of lens selection. Unless you’re a serious amateur photographer (or perhaps an astronomer,) focal lengths, aperture settings and depth-of-focus are as foreign as Greek or Latin. As a result, when you shop for a camera you probably ask the vendor to include a lens in his quotation, with little or no thought as to what kind of lens you actually need.

This is making the assumption that all lenses are created equal. I speak from experience when I say that this is incorrect.

So over the next few days I’ll share some of my rudimentary knowledge of optics, and more importantly, some links to useful web sites, in an effort to clarify why you might want to spend $300 or more on a lens when a $90 version is available.