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.
CLOSE UP SHOOTING CAPABILITIES
The M.Zuiko 40-150mm F2.8 Pro lens is able to shoot at minimum focusing distance of 50cm from the front of the lens to the subject, which is very respectable for a tele-zoom lens of this category. Rival competitor’s lenses can only do 1.2-1.5m closest focusing distance. Having such close shooting distance allows interesting tele-macro shots, and it was indeed interesting to see this lens able to shoot up to 0.41x magnification factor.
Although this is not a macro lens, which it is not intended to be, the close up shooting is a huge welcome, and a long tele close up shot can be quite interesting, creating very compressed shot with very little background, amplifying the subject isolation. I could go very near to the subjects, for example the butterfly shots, as well as the few images as shown after this paragraph. One disadvantage of using long lens for close up shooting is the need to narrow down the aperture to achieve more depth of field, which is often an issue (not having enough zone in focus). The longer you zoom and the nearer you are to the subject the shallower the depth of field.