MrClaws wrote:
Assuming it works the same way as on the 24-70mm:
Set focus at the long end (70mm, or presumably 150mm here) in MF mode. Zoom out (or in again after zooming back) - the lens adjusts to compensate for the shift as you zoom. The optical design, at least on the 24-70, is by no means parfocal, it's just the software correcting for the focus shift using the motor.
Works fine for a gradual zoom in my experience, but it's clearly visible when doing a snap zoom and I wish it could be disabled via the lens station.
Biggest issue on this is probably the torque on the motor not being that great on the bigger Samyang lenses, imo their biggest issue in general. If they had a dual/quad motor design that brief defocus would be much less noticeable because the motor could presumably compensate faster.
What your saying may be true.. It seems like it takes a moment to figure it out and if I pull it back slow enough it tries to stay in focus. Video below.
