Pentax 67 Long Lens Comparison

600mm f/4 400mm f/4 ED(IF) + 1.4X300mm f/4 ED(IF) + 1.4X
A Big Gun Shoot Out
I'm always interested in determining for myself how different lenses compare. I don't shoot lens charts and count lines / millimeter, but I do find that shooting some real-world subjects can tell me a lot about how lenses perform and compare.
Among medium format camera makers Pentax undoubtedly has the broadest selection of long lenses for their 67 camera system. ThePentax 67 IIis the largest camera that one can take into the field that offers very long lenses, suitable for wildlife and highly compressed landscapes — two of my primary pursuits. So, when I purchased the400mm f/4 ED(IF)lens I was particularly interested how it would compare with two other long Pentax lenses with which I had experience.
The Test
Here then are two major tests. The first compares the400mm f/4 ED(IF) with 1.4X Extenderwith the Pentax600mm f/4. The second compares that same400mm f/4 ED(IF) with the300mm f/4 ED(IF) w...