The Nikon D500’s 1.5 APS-C crop when combined with a Nikon TC-300 2x teleconverter gives my Nikon AI-S Nikkor 600mm F/4 ED-IF manual focus telephoto prime lens a 1800mm focal distance. Every bit of that 1800mm was needed to photograph these distant ibis.
The D850 can be used in 1.5 crop mode but in crop mode the D850 has slightly less resolution than the D500. One never knows if additional post cropping is needed so the more resolution the better. In this case the photograph was not cropped in post.
Focus peeking is not available on the D500, so zone focusing was used to render this photograph. Zone focusing employs the distance and depth of field scales available on vintage manual focus lenses in combination with the aperture, to quickly focus on a subject.
At 1/2000 of a second shutter speed, a f/16 aperture focus zone and remote shutter release photographed this flying ibis as heavy winds battered my tripod mounted highly magnified lens.
The effectiveness of zone focusing is illustrated by this flying ibis‘s photobomb. I was pleasantly surprised by this bird in flight photograph.