Having been burgled recently, and having a helpful new for old policy on my insurance, I am starting again building a Micro Four Thirds system having had an E-P3 plus a number of fixed focal length lenses as a system that I had built up over about two years. I have not yet made up my mind which camera body to buy to replace the E-P3, but one that I am seriously considering (pending actually holding and trying it in the shop) is the E-M1, in large part for ergonomic reasons. I have narrowed down my selection of lenses somewhat (I definitely want the 12-40mm f/2.8, the 60mm macro and the Samyang 7.5mm fisheye, and probably the Panasonic 25mm f/1.4, too), I am still very much undecided about what to do for a telephoto lens. Having spent two years working with a collection of fixed focal length lenses, I am leaning now rather towards the premium zooms for flexibility without significant loss of image quality. The overall remaining budget is about £1,000 for the telephoto lens. My various thoughts have included: Panasonic 35-100 f/2.8 A well regarded lens with a good maximum aperture, good sharpness and, from what I have seen, good out of focus rendition, this lens is also wonderfully compact. However, its range is somewhat limited. In my previous system now gone, I had an old 135mm f/3.5 and on occasions found that to be quite a useful length, although that particular lens had serious chromatic aberration problems. Panasonic 45-175 X f/4-5.6 According to at least one review that I read, this lens is as sharp as the 35-100 (although I should be interested in people's views on this); its longer range is, however, balanced by a much lower maximum aperture. Olympus 40-150 f/2.8 This yet to be released lens promises an excellent combination of fast maximum aperture and zoom range, but it could well cost significantly more than £1,000 and the release date is uncertain. Further, this lens will be very large and heavy compared to the Panasonic lenses described above, and I like Micro Four Thirds because I like to travel light. On the other hand, I could, as I did with my 135mm f/3.5, take this lens in a separate bag and only carry it when I think that I am going to need it. Olympus 75-300 f/4.5-6.7 A somewhat slow lens with, from what I understand, moderate optical quality, this would have a lot of reach at the long end but would be less useful (owing to reduced optical quality and maximum aperture) at the shorter end where it would be likely to be most useful. I am unlikely to use something as long as 300mm, so this is probably not the lens for me. Olympus Four thirds 50-200 f/2.8-3.5 SWD These older lenses focus with a reasonable speed on the E-M1 according to a few reviews that I have seen, and are well regarded. Large and heavy, they do come with their own carrying pouch (making it easy to carry them separately and therefore only when needed; the 60mm macro is, after all, a decent medium telephoto), and have the great advantage over the Micro Four Thirds 40-150 f/2.8 that they are available now (and possibly even secondhand for a good price), as well as an extra 50mm at the long end. But just how good is the optical quality really on these (a Lenstip review did not think that these were the greatest, and showed a picture with a decidedly unpleasant out of focus rendition)? I should be interested in hearing from people with experience of these various lenses or any of them as to their handling and optical quality under various conditions, as well as how good that they are at various different sorts of applicaitons.