Big, heavy, expensive, no autofocus, not native m4/3 - what's not to like? I'm using it with Metabones SpeedBooster, which has a 0.7x magnification factor, turning the 55mm Otus into a 38.5mm (79mm full frame equivalent) lens, which works nicely for portraiture. Here are two quick shots from today, taken in a well lit and detailed environment (Bellevue Square shopping mall, observing the aftermath of yesterday's iPhone launch at the Apple Store). It is very difficult for me to find anything that could be done better by any lens on this camera (... besides the big, heavy, no AF, ...). Full size images on Flickr: <a href="https://www.flickr.com/photos/101667287@N08/15296721451" title="140920-104527 by Moritz Berger, on Flickr">"320" height="240" alt="140920-104527"></a> <a href="https://www.flickr.com/photos/101667287@N08/15299485642" title="140920-104621 by Moritz Berger, on Flickr">"320" height="240" alt="140920-104621"></a> Olympus OM-D E-M1, hand held. No PP, raw development default settings with CaptureOne 8 Pro.