I have been using my little Pen F 38 mm a lot over the past month or so, mostly to take pictures of my newborn son. (Sorry, I can't post any of them; my wife has a very strict "no pictures of the kid on the unprotected internet" policy.) For this application, it's usually great. However, I have been dissatisfied with the bokeh from the lens. In addition to having a severe case of ni-sen, it tends to look sort of "swirly." The picture below is a missed shot, but it illustrates this "swirliness" very well. Subscribe to see EXIF info for this image (if available) I didn't quite figure out what was going on until I looked at the corner of another image, and saw this: Subscribe to see EXIF info for this image (if available) An out-of-focus point source not only produces a pretty nasty-looking ring, the ring itself isn't circular! It looks as if the bokeh is terribly astigmatic, with a much smaller extent in the tangential plane than in the saggital one. It's pretty strange-looking, and I haven't seen anything like it on my more modern lenses. It's a bit of a bummer for a bright, portrait-length lens like this, since it puts some pretty severe limits on the sorts of backgrounds that will produce an acceptable image. Perhaps it could be used to artistic ends... Does anyone have experience with the Pen F 40 mm or another similar-length Pen F lens? Do they have this bokeh issue as well?