In the conclusion they write:
Conclusion – Pros
- Superb, almost flawless optics
- Impressive flare resistance
- Fast, silent, and accurate autofocus
- Excellent build quality including weathersealing
Conclusion – Cons
- Unpleasant vignetting in the 50-70mm region at F2.8 on full frame
- Noticeably lower image quality at close focus distances
- No image stabilisation
- Very expensive
In fact, the 24-70mm II follows its big brother, the EF 70-200mm f/2.8L IS II USM (price & specs), in being a lens that’s so good we’ve found it difficult to pick out any significant flaws. It’s superbly sharp, even wide open, but manages to combine this with lovely bokeh. Distortion is pretty well under control (and of course easily corrected in post processing), and chromatic aberration extremely low. Vignetting can be a problem towards the long end on full frame cameras, with a very abrupt falloff in brightness in the corners at F2.8. But again that’s easy to correct, either in post-processing, or in-camera with recent EOS models.
The 24-70mm deals well with difficult lighting too, and handles shooting directly into the sun without much image degradation due to flare. Autofocus is fast and decisive, and we’ve found it to be impressively accurate on higher-end cameras such as the EOS 6D (price & specs). The entry-level EOS 650D (price & specs) can struggle to hit perfect focus every time at F2.8, but that probably reflects more on the camera than the lens. The build quality is difficult to fault too, combining weathersealing with a welcome wieght reduction compared to its predecessor.
Nothing surprising, the EF 24-70mm f/2.8 II was called a peerless performer by the DXOMark’s people.