Interesting patent read. Also in the patent are a 70-200/4, 70-200/2.8, 100-300/2.8, 200-400/4, and finally, a 200-500/5.6. All very similar tin design. All appear to have 18 elements. May have missed something here; this is a hard patent to read. All have a large number of aspheric elements, five, and all of those aspheric elements are located similarly. At least I think so with less than half a cup of coffee in me at this point.
Rereading patent discovered a 60-180/2.8 of similar design, total length of about 200,
Most of the lenses seem to have similar back focus of 37.4 mm which I believe is enough to accommodate the teleconverters. The 200-400/4 has a longer back focus 43.54. The 200-500/5.6 back focus is 37.96. Both lenses are 350 mm long.
Haven\'t we seen some of these lenses already? Might be an omen of what is to come. And if you look at the diagrams, these lenses look to be very highly corrected, something already seen from the 70-200/2.8 and the 100-300/2.8. A person needs to check out just how many aspheric surfaces are in those two lenses. So did. B&H has the 70-200/2.8 Z lens with three aspherics and the 100-300/2.8 with one. The lenses in this patent all have five aspheric surfaces with the ninth element being a double aspheric lens. The IS unit has an aspheric element.
Personally, I think I would stick with my 100-500 as my go everywhere lens. This past week I exercised its full range of focal lengths, The same with my 200-800. Much of the time I carried both lenses, one on the R5, the other on the R5ii. A 150-600/5.6 or variable aperture as long as it was internally zoomed would probably be my preference. The extra 50 mm on the short side is as important to me as the extra 100 on the long end. With a 1.4 teleconverter it would cover most of my needs with my trusty 500/4ii in reserve for extra light gathering. Even with that I would keep my 100-500. Its size and weight are just too nice for a carry everywhere lens.
, O and the 50mm F1.2..... 
