Although made in Japan, Panasonic’s premium lenses produced in conjunction with Leica tend to bump up the price; but even then this lens, which is effectively a stabilised 200-800mm, looks attractively priced. Being not much larger than a full-frame 70-200mm f2.8, this lens is relatively compact. With a metal exterior complete with a nicely designed removable tripod foot, it’s really well made. It also features an unusual collar design that houses the focus limiter and stabilisation controls, so that even when the lens is rotated they’re always visible. There’s even a built-in hood with a separate add-on shade, like you see with some of the big telephoto lenses from Canon and Nikon, although it’s a bit fiddly in use. Sometimes zoom lenses like this can be slow to focus, but that’s not case here. Indeed, AF acquisition and tracking on the Lumix GX8 used for testing targets was often excellent, but at times it would lock and focus onto another target so quickly that it was often simpler to switch to manual and use peaking instead. But what about the optical quality? Lenses like this rarely perform that well at longer focal lengths. Admittedly, it is a better performer at the short end, but it certainly isn’t bad at the long end. Wide open at 400mm it has excellent large structure contrast, but it lacks some of the fine structure or micro contrast of the dedicated telephotos, and doesn’t really improve much on stopping down.