Upload & Sell: On
It depends on the timing and your budget. The 400mm f/2.8 IS Mark II is available right now, although still rare, and that would be my choice, if I were you. Believe it or not, it is actually lighter than the current 500mm f/4.0 Mark I and with the new 4-stop IS and f/2.8 aperture, handheld shooting is possible in a pinch, even for folks in our age group . For an extended shooting time, a monopod will do just fine mainly to support the weight. Again, you can add a 1.4X TC Mark III and you will get the speed of the 500mm but a slightly longer reach. At $11,500, the main drawback is the cost.... . Just my thought, of course.