I’ve owned the 50-200mm f/2.8-3.5 SWD lens since 2008 and with the E-M1 and 3.0 firmware I have been reluctant to try or purchase the 40-150mm f/2.8. A couple of weeks ago I did a shoot with the SWD lens, one of two lenses used. It was a very bright overcast morning with a dense marine layer in the atmosphere – almost dreamlike. Contrast was negligible in anything over 50 feet away. I was having issues with the SWD lens focusing, but knew almost any lens would have some issues with the conditions. Yet as the marine layer burned off I just didn’t feel confident I was getting what I expected, no matter C-AF+TR, C-AF, or S-AF modes. The manual focusing modes are not an issue with this lens as it can be manually focused at any time, in any focusing mode, without the camera trying to refocus when the shutter button is pressed. But if you pause at the shutter press focusing point, the camera may fine tune the manual focus. Anyway, I was not enthused from the expected photos that morning. Right after the shoot I went down to Nelson Photo, one of the local camera stores, and they had a 40-150mm in stock. They were kind enough to let me play with it for about 40 minutes. When Paul pulled out the box - Wow, it is huge! The lens actually takes up a small portion of the box, felt extremely nice, lighter than expected, and in person it looks smaller than in photos on the internet. While comparing the lenses standing up, and flipping one lens top for bottom, the impression of size becomes very close. When adding on the lens hoods of both lenses, the 40-150mm does not seem near as large as in photos. With adapters/convertors added, the size and weight differences are negligible. The 50-200mm has a great nylon case while the 40-150m has a bag. Despite whatever I tried inside or outside the store, the focusing quickness was nearly indiscernible between the lenses. Handling of the two were different - one no better than the other, just different. I might really prefer the 40-150mm after a while, but the 50-200mm with all-the-time manual focusing without doing anything else is great! I ended up walking out without buying the lens, which was not my intent when I walked in. When I got home I processed the photos and was very surprised at what I got from the SWD lens. A lot more keepers than I had envisioned while shooting, and the contrast issues disappeared after some adjustments. I was again surprised when comparing images from the two lenses and the 12-40mm images. The IQ is on par with the 40-150 f2/.8! I didn’t have the 40-150mm long enough to find out where the strong points of the 40-150mm are – but I expect under extreme conditions the 40-150mm would perform better. And as stated before with the SWD lens, the ability to manually focus at any time, overriding or assisting the camera no matter the camera focus settings – again puts it on par with the quick manual focus ability of the 40-150mm. On the rest of the micro four-thirds cameras the focusing quickness easily goes to the 40-150mm. However with the fulltime manual focus capability of the SWD lens on all m4/3s – it easily becomes a viable, less costly alternative. Especially considering the cost difference - $1380 USD for the older lens/adapter vs $1850 USD for the 40-150 and 1.4x convertor (based on Olympus MSRP) and even greater when buying used. For those that already own a 50-200 f/2.8-3.5 SWD lens, in my experience it has become an extremely hard choice to buy the 40-150mm f/2.8 with 1.4 convertor. If a good portion of my shooting involved 100-200mm I would jump at the new lens. But for now the choice will wait until I get a week or more with a 40-150mm lens.