Sony FE 24-70mm f/2.8 GM ( SEL2470GM ) - Review / Lab Test
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Review by Klaus Schroiff, published January 2017
Following the introduction of a trio of "prosumer"-grade f/4 zoom lenses, Sony is now pushing the FE mirrorless system with a set of professional-grade GM (G Master) lenses. Sony emphasizes that they paid special attention on maximum sharpness and bokeh quality ... but then that's what all marketeers are telling us across all brands. We'll see. The first available GM zoom lens is the Sony FE 24-70mm f/2.8 GM. As you might have expected, the pricing is steep at around 2200US$/EUR. However, to be fair that's roughly in line to what we have seen from Canon/Nikon in this lens class.
In terms of size and weight the lens is comparable to its DSLR counterparts albeit this suggests a bit of a problem as well because it's quite a brick relative to the size of the camera (see below). It seems to negate the concept that mirrorless setups should be small(er) really. Anyway, the large max. aperture of f/2.8 simply prevents any size/weight wonders and even Sony can't beat physics thus if we want to have f/2.8 full format zoom lenses that's toad we'll have to swallow.
The build quality of the Sony GM lens is pretty awesome and it's certainly aligned to a professional audience. The extremely solid lens body is based on a dust and moisture resistant design. On the down side, the lens still extends when zooming towards the long end of the range. However, the inner lens tube doesn't wobble even when fully extended. Both the zoom and focus rings operate smoothly. We didn't observe any zoom creeping but Sony implemented a transport lock just in case. A lockable, petal-style lens hood is part of the package.
On the optical side it is worth mentioning that Sony incorporated its new XA element which was manufactured with "extreme surface precision that eliminates optical imperfections for the most beautiful bokeh" ... but more on this later. The new Nano AR Coating is supposed eliminate flare and ghosting - we tend to agree that it helps to reduce such issues as least.
The Sony lens uses a Direct Drive SSM for auto-focusing. It is silent, very fast and fairly smooth so that it is also feasible for getting used during movies (albeit most will prefer manual focusing in this case). Manual focusing still works "by wire" thus you drive the focusing motor by turning the focus ring. However, the mechanism extremely precise and we certainly didn't miss a mechanically-linked focus ring.
|Optical construction||18 elements in 13 groups inc. 1xXA, 2x aspherical, 1xED, 1x Super ED elements|
|Number of aperture blades||9 (circular)|
|min. focus distance||0.38m (1:4.16)|
|Filter size||82mm |
|Hood||supplied, petal-shaped, bayonet mount|
|Other features||Focus-hold button, zoom lock|