Photozone reviewed the 24-70mm GM lens and the conclusion is:
Sony’s marketing made some pretty aggressive announcements at the time of the announcement of their new GM lineup. The Sony FE 24-70mm f/2.8 GM is the first GM lens that we tested here and while we are impressed by the quality, it didn’t really blow off our socks either. Now please note again that lens was tested on a 42 megapixel sensor. This is challenging. e.g. Our full format Canon tests are now based on 50 megapixels and some of you may have noticed that many lenses struggle here as well. So keeping this in mind, the Sony FE 24-70mm f/2.8 GM is actually a very good lens indeed.
If there is a single aspect that disappointed us it’s the bokeh. Or to be precise – the difference between Sony’s claim and reality. Generally the bokeh is good for a standard zoom lens … that is except for the rendition of highlight discs. Sony made quite a fuzz around clean highlight discs but truth remains that they can be rather rough and they aren’t any better than what we’ve seen from Canon or Nikon really.
The build quality of the Sony FE 24-70mm f/2.8 GM is extremely high. The materials are top notch and the weather/dust sealing is the cream on the cappuccino here. However, at that price point we expected no less and the competition is, again, no worse either. Anyway, if you want the best standard zoom lens in Sony E mount, this is certainly it.
24-70mm GM store links: [shopcountry 47915].