Lock On AF Focus Tracking
Images captured to test the accuracy of Lock-On AF: Flexible Spot (medium) when using the Sigma 150-600mm F5-6.3 DG OS HSM (Sports). Images captured at f/6.3 (wide open) using an A7RII and the MC-11 adapter.
The lens, camera and adapter combo is able to track cyclists coming towards the lens at maximum zoom. Only the limitations of the A7RII's Phase Detect Focus area would pose problems for photographers who have had limited experience with panning, e.g. if the subject leaves the central phase detect zone the camera will lose the green focus confirmation - forcing then lens to hunt.
Verdict: Good.
It is easier to lock on to a subject with Sony's native FE70-200F4 G OSS or FE 70-300 G OSS but the Sigma (combined with the MC-11 adapter) currently has no rival in terms of focal length and its 'Lock On AF' option. Without lock on AF you would have to be very experienced at panning to maintain the focus area over your chosen subject.
Lock On AF Focus Tracking
Images captured to test the accuracy of Lock-On AF: Flexible Spot (medium) when using the Sigma 150-600mm F5-6.3 DG OS HSM (Sports). Images captured at f/6.3 (wide open) using an A7RII and the MC-11 adapter.
The lens, camera and adapter combo is able to track cyclists coming towards the lens at maximum zoom. Only the limitations of the A7RII's Phase Detect Focus area would pose problems for photographers who have had limited experience with panning, e.g. if the subject leaves the central phase detect zone the camera will lose the green focus confirmation - forcing then lens to hunt.
Verdict: Good.
It is easier to lock on to a subject with Sony's native FE70-200F4 G OSS or FE 70-300 G OSS but the Sigma (combined with the MC-11 adapter) currently has no rival in terms of focal length and its 'Lock On AF' option. Without lock on AF you would have to be very experienced at panning to maintain the focus area over your chosen subject.