Love that Gannet, hadn't seen that one yet. Did you keep the OS switched on while photographing the BIF Jeff?
Would be interesting to see his results too Jeff. I assume that the results from his set-up but without the tc surpass the sigma?
couple of shots from yesterday ,had a head to head with my lad ,my 1d3 10mp and 70d 20mp and the sigma lens -v- his nikon d810 36mp and 500mm f4vr plus 1.4tc ,the results have even blown me away theres approximately a 5 to 6k price differential there but the sigma blew him out of the water .i have even p/p one of his virtually identical shots to mine myself so they are both done the same .same results .
my shots below the static is with the 70d the flight one is the 1d3
Hard to tell anything Jeff re the test. Would love to see his shots. I can tell you that I shot with a friend who has a d810 and the Nikon 300 2.8 that he shoots with a 2x and 1.4x. The image quality he gets is fantastic and so is his ability to crop. IQ is better than the Canon 7d2 and the C for sure. So much so that I have considered getting that camera or perhaps the Canon 5ds. As for your shots it is hard to tell anything. The head is both over exposed and soft. The flying gull is over exposed and has bad shadows as well. Head looks fairly sharp. Honestly it would be hard to believe that anyone shooting with a d810 and a 500f4 would not come up with considerably better results than those pics, assuming they knew what they were doing and had proper settings and held still when shooting. Something is just not adding up.