Shooters committed to the Four Thirds System, take note. Here is Serious Glass. This pro-caliber 70-200mm equivalent zoom ($2,200, street) -- the world's fastest in its focal-length range -- packs four elements of ED glass, one element of Super ED glass, and all-metal construction with rubber seals to keep out moisture and dust.
This matte-black behemoth has a rubberized and ribbed focusing collar and knurled zoom ring. The former is smooth-turning; the latter, somewhat stiff and overdamped. Four soft-touch, AF-lock buttons surround the outer lens barrel, and the lens both focuses and zooms internally. There's also a removable tripod collar, and three-way focus-limiting switch: close-up (1.4 to 3 meters), nonclose-up (3 meters to infinity), and full ranges. Read the whole review here