Robin Wong tested the new Olympus ZD 12-200 MFT lens and concludes:
I do think that the Olympus 12-200mm is quite an interesting lens. While the lens may not give you the typical Olympus razor sharp image output at the longer end, it performs very well in the 12-100mm zoom range. If you are looking for absolute sharpness, there are PRO grade lenses with superior optics to consider, as well as high quality prime lenses from Olympus or Panasonic. What impressed me most was the flare control of the lens and the fact that despite such a massive zoom range, Olympus managed to keep the size and weight down to a comfortable level. Weather-sealing is a welcome bonus. As long as you do not shoot constantly in dim light, I see no reason the 12-200mm cannot deliver satisfactory results.
Also ePhotozine tested the lens:
The Olympus M.Zuiko Digital 12-200mm f/3.5-6.3 lens is a dream to use, without a doubt. The concept of the all-in-one travel zoom is great, with a long reach and really close focus all built in. There will be many travellers who will take to this lens and produce very memorable images. It isn’t perfect technically, but mega-zooms by their nature are pushing the boundaries and we have to accept that there is some trade-off between quality and convenience. It is also true that many lenses from all the marques may not fare strongly at MTF50 standards, but still have plenty of merit in producing bright, punchy images. The concentration with this lens is weighted towards better performance at wider focal lengths and at the centre of the image field, but the extra reach available will still be appreciated in many situations.
A versatile and easy to use travel lens and, whilst aware of its limitations, recommended.