What 20mm at f/1.7 actually gives you
20mm is wide enough to take in interiors, landscapes and architecture without the pronounced edge stretching of an ultra-wide. On the Micro Four Thirds bodies it covers, it frames like 40mm would on full-frame.
f/1.7 is fast enough to keep shutter speeds up in poor light and to separate a subject from its background clearly.
Size, close focus and filters
At 87g (3.1 oz) it is light enough that it stops being a decision — the kind of lens that stays on the body or in the bag without thought.
It focuses to 20cm, which is close enough to fill the frame with small subjects.
Filters are 46mm — 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 and stabilisation
Autofocus is driven by a DC 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.
