Review by Sebastian Milczanowski, published Jan 2014

Lens kindly provided by Hendrik Baumgarten.

Introduction

After five and a half years of Micro-Four-Thirds (MFT) Olympus and Panasonic cover the entire range from 7 to 300mm, including some excellent fixed primes like the Olympus 75mm f/1.8. However, friends of fast zoom lenses were left staring at nothing until the launch of the Panasonic 12-35mm f/2.8 in mid 2012 and only more than one year later Olympus finally joins the league of MFT prime zooms.
Therefore Olympus raises the bar, at least on paper, by spending 5mm extra focal length as well as an outdoors body not only prepared for dusty and rainy but also chilly weather conditions. Anyhow, although the Olympus 12-40mm is an f/2.8-lens in terms of speed, experienced MFT users are aware of the less impressive depth-of-field capabilities due to the sensor size.

Nevertheless, let’s have a closer look at this beauty.

Upon the first contact you will realize that this lens is different comparing to the other MFT lenses as the speed and the weather sealing as well as the pro-finish result in a big and heavy lens. In fact with its 382g it feels too heavy for the Panasonic GX1 with its 320g, but this will be less of a problem for Olympus E-M1 users for sure.
Furthermore, Olympus spend two unique lens features to make photographers and movie enthusiasts life easier. On the one hand the manual focus clutch mechanism, which switches easily between auto- and manual focus and on the other hand the L-FN button, which temporarily prevents unwanted autofocus operations in case of accidentally crossing objects. Additionally, you can link this button to an Olympus camera setting.
With other words, the build quality of the lens is excellent and control operations feel adequate for a lens at a price tag of €999.

Olympus is promoting “an unbelievably fast AF high-performance” in combination with the Olympus OM-D and this applies also for our Panasonic cameras. Moreover, talented filmmakers will love the silent autofocus and the focus distance scale.
Finally, the only real downside for Panasonic users might be the missing image stabilisation, which is less of a problem for new Panasonic cameras with integrated image stabilisation like the GX7.