This is a lens that we own. Olympus OM-D E-M1X + M.Zuiko 75-300 mm f/4.8-6.7 @ 300 mm, efov 600 mm, f/6.7, -0.7 step,1/500, ISO-2500, 16 mm extension tube used Technical Note I use the 75-300 on an Oly body. I find sharpness at 300mm is good, and the reported softness is more due to very narrow DOF, atmospheric conditions at longer distances, and camera shake. YMMV. Set your camera on a tripod or secure it in place by some other means. Set the zoom to 75mm and start slowly zooming all the way to 300mm, while looking at the live view (magnified view might be helpful here). Do note if during the zooming the image moves around additionally to being magnified. If it does by anything more than a small amount (the barrel might wiggle a bit when operating a zoom ring), then you have a broken lens, return it. Here are the links for purchasing the lens and accessories. Buying from those doesn’t cost you extra, but I get at small % from the sale.

I have to do a side-by-side comparison of the two lenses shooting off the tripod with the OIS turned off, but the limited hand-held tests I've done so far seem to indicate that their optical quality is roughly on par with each other. However, the Olympus lens seems to deliver much more consistent quality resulting in a much higher keeper rate than the Panasonic. And the things I haven’t tried, because they are in the higher-end cameras, not in my Olympus PEN PL9. At the 75mm end of the zoom range, the diagonal angle of view is 16 degrees, equivalent to that of a 150mm lens in a 35mm system.That being said the Olympus 75-300-II is sharper than the Panasonic 100-300 because it doesn't have the moving OIS unit inside. Overall neither is particularly sharp at 300mm.

Olympus 75-300 creates a crisper, more pleasant (to my eye) bokeh than Panasonic 100-300 whose bokeh can be mushy and dull looking.has a little bit bigger apertures at both ends of the range, but I'm not sure if that is super important to me... I have had very good results with the 75-300mm 11, as well as the Panasonic 100-300mm but the one thing that I do not understand is that both the 75-300 as well as the Panasonic 100-300mm would not focus at the longer end even though the camera is beeping focus confirmation. Coming from a Nikon DSLR (which I still have) I find this strange. Never had a camera that confirms focus when you know it is not. Maybe someone could explain this to me (Olympus E-M1 is the camera I use) Vignetting is also suitably low, though that is expected in a lens with a slow-variable aperture. Control of chromatic aberration is generally good, but it could be noticeable in certain (high-contrast) images at 100mm and 150mm. Yes we will see if I like the Olympus 75-300 any better than the Pana 100-300. If not I will return it. I’ve taken some very good pictures with the Pana 100-300mm though but I don’t very often carry it with me. It was the test on Photozone that made me buy the Panasonic 45-150mm as I (like you) trust their tests. It did very well on that test and it handles very well and is very easy to carry. I think the idea of the Micro Fourthirds sytem is that you easily can bring your equipment with you and still have a high quality equipment. Everyday when I walk my dog I use to hang the camerabag on my shoulder and also bring it with me on other occasions. If I don’t I will miss many good opportunities to take pictures. On my walks I do very seldom see any other people carrying cameras and especially not big DSLR:s! Recently I started seeing the rise of Micro 4/3 in wildlife. The main advantages are lower prices, lower weight, and in-body image stabilization (IBIS) of Micro 4/3 cameras. All this, arguably, without significant loss of image quality in bright light.