Here is a portrait made with the Sony FE 100-400MM F/4.5-5.6 GM OSS and 1.4X teleconverter @560mm. I love the versatility this combination offers with a short minimum focusing distance when the subjects get close :)
Wood Duck PORTRAIT (Aix sponsa, Canard branchu, WODU) from my Better than Bosque workshop. Bosque del Apache National Wildlife Refuge, San Antonio, New Mexico, USA. Image Copyright ©Christopher Dodds. Sony Alpha alpha 1 Mirrorless camera & Sony FE 100-400MM F/4.5-5.6 GM OSS Lens with Sony FE 1.4X Teleconverter @560mm ISO 1,2500, f/8 @ 1/2,500s. Full frame image. Manual exposure.