[Kratz] knew all this, but it didn’t stop him from looking for a cheap lens deal over on eBay. He found a broken Nikon DSLR ... parts with the external aperture control arm.

And that point is that many photographers wouldn’t class the f/2.8 of even high-end zooms as a ‘fast’ aperture, preferring the quicker aperture of a prime lens. And when it comes to prime ...