from slrgear.com: Optically the Olympus 75-300mm does very well, but not where you'd want it to - it's super-sharp at 70mm, not at the 300mm where I suspect the grand majority of users will want to use this lens. At 300mm, it's only above average, and there's noticeable chromatic aberration.
Overview

Description by Olympus:

Specifications
Initial Price: 
$800
Release Date: 
08/2010

More specs revealed about the Olympus XZ-10 camera and M.Zuiko Digital ED 75-300mm f/4.8-6.7 Mk. II Lens.

Lens first: Everything appears unchanged, except for the new ZERO coating (ZUIKO Extra-low Reflection Optical Coating), same as the one that adorns many of Olympus Prime Lenses. Availability set to March 2013. The lens is also slightly redesigned, it looks a bit less like a designer flower-vase now and more like a proper lens. 

As for the XZ-10, it is a smaller, lighter and cheaper successor to the similarly looking XZ-2, with little else in common. The lens is now a 5x optical zoom of 26-130mm F1.8-2.7, and the sensor is very sadly a smaller 1/2.3" 12 Megapixel story, that kinda puts this cam out of the 'prosumer' range we're covering at Estiasis. If this digicam is still of any interest to you, grab your Google transgorbler and head over to Digicame.info for the rest of the spec list. . . . read more

Olympus to release a new 75-300mm zoom lens and a successor to the XZ-2 soon.

Too bad it will be a dark f/4.8-6.7 lens again. Something must be done to get the message to Olympus, its users screaming about the need of fast zooms. 43rumors has the story:

I finally got some bits about the next Olympus announcement that will be made right before the CP+ show start in Yokohama (January 31th). The discontinued Olympus 75-300mm MFT lens will be replaced by the new 75-300mm II F4.8-6.7 ED lens. And there will be a a new Olympus XZ-10 that is smaller and lighter than the current XZ-2. It has a f/1,8-2,7 lens and will be cheaper than the current XZ-2 model (here on eBay).

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