Review by Klaus Schroiff, published May 2017

Introduction

The Leica lens is targeting the high-end of the market and this is reflected in the quality of the construction which is a step above Panasonic's usual offerings. The lens body is mostly made of metal which feels quite classy. The zoom- and focus-rings operate smoothly. Typical for most standard zoom lenses it extends when zooming towards the long end of the range. The inner tube doesn't wobble even when fully extended. The lens is also weather-sealed and "frost-proof" down to -10C. Unlike most of the affordable Panasonic lenses, the Leica has a dedicated AF and OIS switch. A petal-shaped lens hood is part of the package.

If you "shake" the lens you may notice that it "rattles". There's nothing wrong with this - what you hear is (most likely) the focus group. If you half press the shutter release button (in AF mode), the rattling is in fact gone - thus the AF group is tightly kept in place when doing so. The focus group seems to have a relaxed setup in order to allow speedy focusing. Fujifilm lenses have a similar design.

The AF motor is, as mentioned, very fast and noiseless. As usual manual focusing works "by wire" but you barely notice the difference compared to a mechanically-coupled system. Panasonic's Power OIS (image stabilizer) offers a "gain" of around 2-3 f-stops (real life) which is somewhat less than we expected here. If you own one of Panasonic's latest generation Lumix cameras, you can also take advantage of "Dual IS" thus the in-camera stabilizer can work in conjunction with the in-lens stabilizer. Panasonic doesn't provide any figures here about it's reasonable to assume an additional gain of 1.5-2 f-stops (we didn't have a Panasonic camera to test this). While this is good in absolute terms, it stays short of Olympus' Sync-IS (claimed up to 6.5 f-stops).