What 28-105mm at f/2.8 actually gives you
28-105mm sits close to the way the eye takes in a scene, which is why this range tends to get used as a general-purpose focal length.
f/2.8 held across the zoom range is the working standard for a fast lens — a stop or two of low-light headroom over a kit zoom, and noticeably more background separation.
Size and filters
At 1055g (2.33 lb) it has real presence on the front of a camera, though it stays hand-holdable for a session.
Filters are 82mm — worth checking against what you already own, since polarisers and ND filters at this size are reusable across any other lens sharing the thread. A dedicated aperture ring gives direct control without going through a camera dial, which mostly matters for video work.
Autofocus, stabilisation and weather sealing
Autofocus is driven by an HLA motor.
There is no optical stabilisation in the lens, so handheld steadiness depends on the body having IBIS, or on keeping the shutter speed up.
The barrel is weather-sealed, so rain and dust are a manageable risk rather than a reason to pack up.
