(Bought for Panasonic Lumix DMC-GF1 M4/3) First impressions and beyond; Firstly it is exceptionally well packaged and protected, comes with lens cloth and nylon pouch. Unpacked, the lens is a nice and large lens with clear glass and multi-coated, as well as excellent workmanship. A well-sized rubber focus ring that rotates smoothly in either direction without sticking has plenty of travel due to close focus capability. The locking ring is easily accessible and large enough to rotate easily and has a good "Goldilocks" factor; it turns neither too hard nor too loose, but right in the sweet spot. The apertures range from f/2.8 (a really good and fast aperture for a wide-angle lens of this price) to f/22 at half an aperture. The assembly/disassembly of the lens is easy and smooth, it fits tightly without play. The lens hood is easy to put on and take off and fits securely (note: don't forget the button on the side of the lens hood when attaching/detaching). The first test I always do with a new lens for this camera is the flash (top left position) because it really is a snapshot camera. And because the lens is large even without a lens hood, it REALLY blocks some of the light in the bottom right corner of the frame, which might bother some. The lens hood blocks even more. I've only done initial tests, but so far the lens has good color rendering and contrast. Good sharpness, which, as is usual with most lenses, already starts to shine at f/5.6. Fully open at f/2.8 is obviously not that good, but it's good enough and f/2.8 is an acceptable compromise. There is no barrel distortion and no corner-to-corner exposure vignetting that I could see. Of course, being an ultra wide-angle lens, there is stretch distortion towards the edges of the image and sharpness falls off towards the edges as you open the aperture, but that's neither excessive nor unacceptable for a lens in this price range. All in all, this is a really good lens. Wide angle lens with quick stop which is what I've been looking for since I got this camera. The only downsides are the size and weight (which can't be beat given the technical requirements required) and the price which I'd like maybe $30 cheaper but for that they would need it as an f/3.5 lens or f/f build /4. And I love that f/2.8 lens so it's cool man. Although I still have a lot to test, if you understand its features I can recommend this lens. Weight, size, fully manual focus and aperture settings. I'll personally be using this as my new go-to lens for the Micro 4/3 - I love that I finally have a decent wide angle lens!