I finally went mirrorless a few weeks ago and bought an Olympus E-M1 with the 12-40 f/2.8 and absolutely love it after spending 2 weeks on vacation shooting it.
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An older pic from back in March shot with my old Sony A57
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New pic from just a week and a half ago from a wildlife refuge just out of Eureka CA, shot with the E-M1, RAW to TIFF in the Olympus RAW converter and then further editing and B&W conversion in GIMP.