Originally posted by biz-engineer I was shooting along with a professional using two D810 bodies mounted on 600 f4 and 200-400 f4 (worth $25K). It was amazed that some of his shots were out of focus... and while I did not stay as long as him on the location, I have to say that what I got from the K1 with the same framing and lighting is pretty much identical to what he got with his Nikon gear. Get what, he was shooting at f8 to prevent DoF issue. The difference is essentially that the Pentax gear is sub $4K, a lot cheaper than the Nikon gear. What I got back from that experience was that framing and lighting was what made the difference between a good shot and a bad shot, and I would get better images with his $25K gear. But of course, owning this Nikon gear is no much "sexier" than owning a Pentax gear, that's marketing.
I would think naively that regardless of price a good 600mm f/4 + TC would have helped significantly on the 2 photos you just submited
But yes this is first being at the right place at the right moment, knowing what compo etc to capture and finally knowing enough of your gear to make it happen.
I can say still my 55-300 need f/8+ and isn't very sharp at 300mm. This limit sometime the bokeh I get and also the possibilities of cropping. This is always a idea of diminushing returns.
But yes when the light is not good or the subject too far away, the best gear doesn't make it look nice. It just make it less bad.