The Sony 70-400 mm G is one of the Sony lenses from the Gold series, the professional Sony Alpha lenses. The Sony 70 – 400 mm has a full aperture, depending on the focal length, between the aperture 4 and 5.6. The lens is suitable for both a camera with an APS-C sensor and a camera with a full-frame sensor. We have tested the camera on the Sony A77, a camera with an APS-C sensor.

The Sony 70-400 mm increases in length substantially as you zoom to 400 mm. The freely added lens hood makes the lens even greater than shown here.
Converted to a lens on a camera with a full-frame sensor, the combination of Sony 70-400 mm and the Sony A77 gives a 6x zoom range of 105 to 600 mm.
Construction and autofocus
The lens is built like a tank and is finished in stylish silver. On the lens are a few buttons, with which you can turn of the AF or limit the focus range, allowing the AF time to be shortened.
Usually, the zoom ring is on the body and the focus ring at the front lens. With this lens, it is the other way around. This takes some getting used to.
The drive of the SSM autofocus (Supersonic AF Motor) goes pretty fast, but in low contrast or in the dark, there is some searching sometimes. The autofocus then does not have enough contrast for fast focusing. This is a common phenomenon with extreme telephoto lenses with a maximum aperture of 4 or higher.
Image stabilization
The in-camera image stabilization of the Sony A-77 in combination with the Sony 70-400 is excellent. We have tested the image stabilization at a focal length of 70 mm. Without image stabilization, you can still take reasonably sharp shots to 1/50 seconds. With image stabilization to 1/6 seconds. That is a profit of 3 stops.
Vignetting
Because the lens is designed for use on a camera with a full-frame sensor, there is hardly any vignetting. Even at full aperture, the maximum vignetting is less than 0.4 stops. Very occasionally, vignetting may be visible in practice when using the Sony 70-400 mm on a camera with an APS-C sensor.
Flare
The Sony 70-400 mm has virtually no problems with ghosting. With difficulty it worked to create flare with the Sony 70-400 mm without lens hood in the studio. If you use the supplied lens hood, it is virtually impossible that you suffer from ghosting. In this practice shot of the moon, no flare can be seen, while the Sony 70-300 did show flare under similar circumstances. A top performance of the Sony 70-400.
Resolution
The Sony 70-400 mm is a lens that delivers sharp images. Not only over the entire zoom range, but even from full aperture. That is a very good performance.
Many telephoto zoom lenses become less sharp as you zoom in further. But that does not apply to the Sony 70-400mm. The resolution at 400 mm is as high as at 300 mm. Very good.
Chromatic aberration
The chromatic aberration of the Sony 70-400 mm is low at all focal lengths. In practice, you will encounter no visible chromatic aberration in images taken with the Sony 70-400 mm.
Conclusion Sony 70-400 mm f/4-5.6 G SSM review
Pros
- High image quality, even at the longest focal length
- Zoom lens with extremely long focal length
- Large zoom range
Cons
- Big and heavy (1.5 kg)
- Expensive
- Autofocus sometimes searches with little contrast
The only disadvantages which we can think of for this lens (that it is large and heavy, and that the price will be high for some) are obvious. If this is not so important to you, the Sony 70-400 mm is an absolute must.