I used to have a Panasonic 45-200mm lens for my GH4. The ratings for this lens are misleading as the 45-200 sucks for professional photographers/videographers. None of the images were sharp/sharp. I was very skeptical that this one is any better, especially at a higher price point. This seller was the cheapest I could find for a new one. Damn cheaper than used B&H. Despite the fact that the instructions and everything was in a foreign language, this lens is great. The focus is 10 times better. Perhaps the only downside to this lens is the zoom. Feels really stiff and doesn't seem to flatten out over time. It's hard to turn at first, then suddenly gives way. Cannot scale smoothly.