Sony 70-200mm f/2.8 SSM G (SAL-70200G) - Full Format Review / Lab Test - Analysis
Lens Reviews - Sony Alpha (Full Format)
Article Index
Introduction
Analysis

Distortion

The Sony lens produces slight to moderate barrel distortion at 70mm (1.2%) and moderate pincushion distortion at 200mm (2%). The two opposing distortion types even out in the middle range.

Move the mouse cursor over the focal length text marks below to observe the respective distortions
70mm 135mm 200mm

The chart above has a real-world size of about 120x80cm.

Vignetting

There's an average amount of vignetting for a such lens used on a full format DSLR. The light falloff is often visible at max. aperture (0.9-1.4EV) but this isn't quite as bad as for an ultra-wide or ultra fast lens. From a real life perspective the issue is negligible from 70mm f/4 and 135/200mm f/5.6.

MTF (resolution)

The Sony G lens produced very good resolution figures in the MTF lab. The center image portion is generally excellent throughout the zoom range straight from f/2.8 all the way up the f/11. The borders are very good at 70mm f/2.8 whereas the corners are "only" good at this setting. However, the quality increases continuously and reaches an excellent if not outstanding level at 70mm f/8. There's a similar border/corner characteristic at 135mm/200mm albeit on a slightly reduced level.

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

Lateral chromatic aberrations (color shadows at harsh contrast transitions) are very well controlled. You may still be able to notice traces of CAs (~1px) but this is generally a non-issue in field-conditions. Needless to say but you can correct or at least reduce lateral CAs during post-processing e.g. via Photoshop.

Bokeh (out of focus blur)

The quality of the bokeh (the out-of-focus blur) is a major aspect in this (large aperture) lens class. Unfortunately this isn't exactly a strength of the Sony lens. Out-of-focus highlights are circular but show a fairly obvious outlining specifically around 135mm at f/2.8 and busy backgrounds are not handled overly well. The situation improves when stopping down. The situation seems to be better at 200mm. That all said you can surely achieve a very good bokeh in non-critical scenes but there're simply lenses with a better quality here.

Longitudinal (Axial) Chromatic Aberrations (LoCA)

LoCAs (non-coinciding focal planes of the various colors), sometimes called "bokeh CAs", can be an issue in the field. As you can notice below the halos have different colors - magenta (red + blue) in front the focus point and green beyond. The fringing is very pronounced at f/2.8 and there're still visible traces at f/8. This is a bit disappointing regarding the number of UD elements used in the lens design.

Move the mouse cursor over the f-stop marks below to observe the respective LoCAs
f/2.8 f/4 f/5.6 f/8

Verdict

The Sony 70-200mm f/2.8 SSM G can give you very good results on a full format DSLR but it is not a lens without issues. It is certainly sharp - the center image portion has an extremely high quality at all mainstream settings and the borders are generally very good. The corners are a little soft at 135mm+ at max. aperture but they recover towards medium aperture settings as well. The amount of vignetting is about typical for a lens in this class - you will be able to see some light falloff at f/2.8 in critical scenes but the issue is mostly resolved at f/4. Image distortions are moderate at the extreme ends of the zoom range but not overly significant in the medium range. Lateral CAs are very well controlled which is certainly a highlight of this lens. The primary downside of the lens is the quality of the bokeh which can be sort of rough in certain situations although it is naturally possible to achieve a good blur quality if the focus background is not too busy. The amount of bokeh fringing is also higher than average unfortunately. Typical for a professional grade lens the build quality is absolutely exemplary and it's a joy to experience the fast and silent AF (SSM). The pricing is fairly steep at around 1700EUR especially when compared to third-party alternatives.

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