Panasonic LUMIX G VARIO 100-300mm f/4.0-5.6 II POWER O.I.S. (H-FSA100300)

This Panasonic zoom spans 100–300mm on Micro Four Thirds bodies, a range aimed at distant subjects such as birds, wary animals and outdoor sport. It is the second version of the design, introduced in 2017, and it remains in production.

Wildlife is the natural territory here: garden birds at a feeder, deer across a field, and games played at the far side of a pitch. The f/4–5.6 maximum aperture is the main trade-off. You need decent light at the long end, or a willingness to raise ISO. In return, the zoom stays small and easy to carry.

At 1 lb 2.3 oz (520 g) and 4.96 in (126 mm) long, this is a light, compact package for a zoom that reaches 300mm. You can carry it all day on long walks. It takes 67mm screw-in filters at the front thread.

On a Micro Four Thirds sensor, 300mm frames a distant subject far more tightly than the same focal length would on full frame. Few distant animals tolerate an approach, and this reach saves you the attempt. The 100mm end steps back for context, such as an animal within its habitat, and gives you room to follow fast movement.

A single zoom ring covers the whole range, so you can reframe without shifting your feet when the subject moves. A bird hopping between branches or a play swinging your way can be followed with one turn of the ring.

The maximum aperture runs from f/4 at 100mm to f/5.6 at 300mm. In bright daylight you will rarely notice the ceiling. Under overcast skies or at dusk, expect slower shutter speeds or higher ISO. The long focal length still helps throw a busy background out of focus around your subject.

Closest focus sits at 4.9 ft (150 cm), close enough to frame a confiding garden bird or a butterfly working a flower bed. That distance also keeps your shadow off skittish subjects.

The in-lens POWER O.I.S. stabilisation helps reduce blur from camera movement at these long focal lengths. The correction lives in the lens rather than the camera body. Handheld frames at 300mm become more usable in morning or evening light. It cannot freeze a moving subject, so birds in flight still need a fast shutter speed.

The lens is weather sealed, which helps keep dust and moisture away from the internal parts. That cover suits long waits at a wetland hide or a dusty trackside.

There is no zoom lock, so the barrel cannot be fixed at a chosen focal length. The elements also carry no fluorine coating.

One low-dispersion element helps reduce chromatic aberration, where different colours focus differently and leave coloured fringes along high-contrast edges. Fringes tend to show on a bright bird against a pale sky, a common frame at this focal length.

Focusing works by moving elements inside the lens, so its length stays constant while you focus.