So I finally pulled the trigger on a used D850 after years of shooting with my old D7100 and man the files are huge lol. I'm mainly looking to get into some serious birding and wildlife photography since I just moved closer to the Everglades and there's so much stuff to shoot out here. My budget is pretty tight though since the body took most of my savings so I'm capped at around 1300 or maybe 1500 if I stretch it. I've been looking at the Nikon 200-500mm f/5.6 which everyone seems to love for the constant aperture but then I see the Sigma 150-600mm Contemporary and that extra 100mm on the reach sounds really tempting for those far away herons. I've heard the Sigma is a bit lighter to carry around all day which is a big plus for me because my back isnt what it used to be and I prefer shooting handheld when I can. Then there's the Tamron G2 which people say is better built but I dont know if it's worth the extra cash. If I go with the Nikon am I gonna regret not having that extra reach or is the image quality really that much better on the D850 sensor? Just trying to figure out which one is gonna give me the best bang for my buck for a hobbyist setup...