What 70-300mm at f/4 actually gives you
70-300mm is a short-telephoto framing: tight enough to isolate a subject, wide enough to keep some context. On the APS-C bodies it covers, it frames like 105mm would on full-frame.
f/4 is a moderate maximum aperture. There is less low-light headroom and less background blur than an f/2.8 lens gives, which is generally the trade for lower weight and cost.
Size and filters
At 580g (1.28 lb) it sits in the middle for handling: substantial enough to feel planted, light enough not to dominate the kit.
Filters are 67mm — worth checking against what you already own, since polarisers and ND filters at this size are reusable across any other lens sharing the thread.
Autofocus, stabilisation and weather sealing
Autofocus is driven by a Linear motor.
Optical stabilisation is built in, which stacks with in-body stabilisation on bodies that have it and does the work alone on bodies that do not.
The barrel is weather-sealed, so rain and dust are a manageable risk rather than a reason to pack up.
