The following has been taken from Robin Wong’s review that can be found in full here
‘At this moment in my personal scoring system the M.Zuiko 40-150mm f/2.8 is the BEST Micro Four Thirds lens ever’
Let’s start with something that everyone wants to know about the lens: how sharp is the M.Zuiko 40-150mm F2.8 Pro lens?
Looking at the MTF chart, the sharpness of this lens surpasses even the legendary Super High Grade ZD 150mm F2, and my expectation was indeed very high. I have shot enough images to conclude that the M.Zuiko 40-150mm F2.8 Pro is extremely sharp, even at wide open aperture F2.8. The amout of fine detail this lens is able to resolve is amazing, with plenty of micro-contrast. Every single image I have shot with this lens came out richly detailed and there were a few moments I thought I was actually seeing results similar to what I would expect coming from the M.Zuiko 75mm F1.8 lens!
Shooting at wide 40mm, all the way to 150mm, the lens showed no sign of softness, and I had a difficult time figuring which focal length was the optimum (I gave up). And like all Olympus M.Zuiko lenses the lens is already very sharp at wide open aperture F2.8, and it is even better at F3.5 and F4, which I often stopped down to when shooting subjects in near distance to achieve sufficient depth of field. The sharpness is also uniform from edge to edge of the frame, showing no corner softness.
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