Sigma 150-600mm f5-6,3 DG DN OS [S] Sony E-Mount

I was a bit worried about handholding such a long lens, but the build quality feels solid and well-balanced on my α7 IV. The autofocus is snappy enough to track birds in flight without much hunting. Definitely worth the upgrade from my old adapted lens setup.

The stabilization on this is incredible — I can shoot handheld at 600mm and still get sharp bird photos in the early morning light. Auto-focus locks on fast enough to track swallows in flight.

I was worried this lens would be a beast to carry, but the zoom ring is silky smooth and the built-in OS made handheld shots at dusk usable. It's definitely heavy, though the image stabilization compensates more than I expected for its weight.