I'm still getting to know the Olympus 40-150mm f2.8 and found some cooperative Chipmunks to help out. The lens focused very fast on these little critters even in tough contrasty light, and heavy shadow.
For this shot below, I tried the 5 axis image stabilization on the OMD EM1, dropping the shutter to 1/40th of a second. This proved to work very well, but keep in mind, I would not do this had the chipmunk been moving.
I do find myself at the end of the focal range often (150mm) and can definitely see how the 1.4 extender would be useful. I'm very pleased with the performance thus far however.
I also found this terrific rusty bike over by the beach and made a closeup to show the texture. This lens would have let me get even closer if so desired with pretty great macro capability.
Just before heading home these dramatic beams of light streamed down from the sky.