A screen clip at 100% from Nikon ViewNX showing focus point on the tree branches the Heron is sitting on, but note how the reeds in the background seem sharper. The lens is Sigma 18 - 250mm f3.5-6.3 DC OS HSM
Nikon D5000
,Sigma 18-250 f3.5-6.3 DC OS 1/500s f/6.3 at 250.0mm iso800
full exif