This is an Olympus lens for the FourThirds system.
It covers the longer telephoto zoom range of 70-300mm, which due to the 2x crop factor of the FourThirds system gives the equivalent horizontal field of view as a 140-600mm lens on a full frame sensor.
The zoom function is a standard twist type, although as an observation the direction is opposite from that of Sony and Canon lenses. It takes about 1/4 turn to go from each end of the zoom range. The action feels good with enough but not too much resistance. The inner barrel that extends is low in weight and on my sample no creep occurred.
The front section extends during zooming, and also when focusing closely. The front rotates when focusing. Auto-focus speed is reasonable and not particularly fast or slow. There is a switch on the lens where you can select AF or MF. Common to their other lens it features the focus by wire system.
In addition to its ability as a regular zoom, it also claims to be macro. The lens has a maximum magnification of 0.5x (1:2) at 300mm and its minimum focus distance of just under 1m. Again considering the crop factor of the FourThirds system, this is equivalent FoV to 1:1 on a full frame sensor. As a minor negative, the AF only works down to a distance of 1.2m, which is about 0.33x or 1:3 magnification.
So what we have here is a lens that is capable of photographing small subjects from a long distance, and also has a strong macro potential. How does it work in practice?
I find this close to being my perfect outdoor lens, considering my style doesn't cover wide angles. Distant subjects, general close ups and macros are covered well by this single lens. Picture quality is generally very good, with no significant negatives that I can see. In particular, CA is practically non-existent in the photos I've taken and maintaining good sharpness at the long end.
To me the lens doesn't have any significant weaknesses given the system and placement. I personally don't like the manual focus by wire system, as I don't feel as connected as I would with a normal direct mechanical link. And as always the AF speed could better and bigger apertures would be handy, but that's another lens.
I've added a small selection of my photos in the gallery thread