Summary: I have a hacked Panasonic Lumix GH-1. I have the 20mm 1.7, which is sharp. I had tried the 14-42 f 3.5-5.6 zoom and I didn't like it. The videos weren't sharp and it was clunky when zooming. I wanted a zoom but was looking for a bargain so I purchased a used 40-150mm Olympus for a total cost of $95.00. I only used it once so far but the video was excellent. The color was very good and the video was sharp. Photos were better than expected.
Summary: When I bought my PEN e-PL1 it came with the first generation of this lens(M. 40-150mm F4.0-5.6). The lens was good for photos, but there were two problems while taking video - lens did not focus while zooming, and there was fairly loud noise produced by zooming mechanism, which ruined concert recordings. I gave PL1 to my son, bought a PEN e-P3 with just a 14-40 lens. Recently I bought a refurbished M. 40-150mm F4.0-5.6 R from Olympus website.
Summary: I wanted to add a new lens to my EPL1 and this was the perfect addition. I can exchange it quickly and the quality of the product is really good. The 40-150 mm is a great range. It does a great job taking pictures of landscapes, and outdoors in general. I recently took it to a trip to Miami and the results were amazing. If you have micro 4/3 camera this is great addition to your camera bag.
Summary: As being a cheap 80-300 (35mm eq), this lens has been a good buy. Took pictures of pond and water features during waning light. Picture came out really nice. Of course not all pictures were clear as slower shutter speed created some shake (even BIS cannot do it all)
Summary: This lens is pretty much a must have lens for Olympus M4/3 camera users because it's such a screaming deal. It's truly great up to 100 mm and very good beyond that. Most of the time I'm using it to shoot wild life fully zoomed at 150mm and the pictures are amazing. It shoots best between f5.6 and F11 so it's not exactly a fast lens, but it focuses quickly (at least on my E-PL3) and is really sharp with great color. Is it a "Pro" lens?