DxOMark has just tested the new released Sony FE 100-400mm f/4.5-5.6 GM OSS lens (Adorama/Amazon/B&H Photo). According to DxOMark result, this lens is the sharpest lens of all telephoto zoom lenses. You can take a look at below:
Conclusions from DxOMark:
Telephoto zoom lenses like this tend to be quite large and unwieldy, and are inclined to be sharper at the shorter end of the zoom range. They also often have troublesome chromatic aberration that contributes to the decline in image quality, particularly at the longer end (where you need it the most).
While there has been some slightly improved performance in more recent models, such as the Canon EF 100-400mm 4.5-5.6L IS II, Sony’s new FE 100-400mm F4.5-5.6 GM OSS stands out not only for its seismic shift in sharpness, but also for being not much different in size to the FE 70-200mm F2.8. Best of all, perhaps, is that for once there’s a tele-zoom that offers seriously impressive image quality at that prized 400mm focal length.