2 extra low dispersion, 1 super extra low dispersion
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It is the best ultra-tele available for Sony. It's super sharp, focuses super fast and super close and has three focus lock buttons [...] Bokeh is excellent [...] It's ultra-sharp, even wide open at any zoom setting.
29 [Tested on 42 MP camera] 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.
Optically, it is excellent throughout the entirety of its focal length range, with an incredibly even performance from corner to corner. There is minimal chromatic aberration, very little flare when shooting against the light and vignetting is well controlled for a lens of this type. Probably the most surprising element is how well the lens can keep focus when photographing action [...] The only genuine gripe I have with this lens is its weather sealing.
There has been a gap in the Sony mirrorless range and the new Sony FE 100-400mm f/4.5-5.6 G Master lens fills it perfectly. There is no alternative, although we can pitch its price up against what other marques offer and see that it is somewhat higher in cost than most offerings. However, it is also a superb lens in every way and, especially coupled with the new A9 body, more than capable of doing some amazing things for wildlife and sports photographers.
I’m a little conflicted on this particular lens. One one hand, it is a well-executed, competitive package that is great to use. On the other, it is priced like a premium lens – easily the most expensive lens with this focal range. [..] and while the 100-400GM is an excellent lens, I’m not sure that it is a superior lens.