The built-in 1.4x teleconverter instantly shifts from 600mm f/4 to 840mm f/5.6, paired with a silky swift VCM autofocus system for fast subject tracking. Its 26-element, 20-group optical formula and VR stabilization deliver sharp hand-held results despite the 3266g weight. This super-telephoto prime is best for birding and wildlife photographers who need dual focal lengths with uncompromising autofocus speed in a single lens.
