I wrote in an earlier post how camera reviewers are often blamed for inaccuracies or omissions in their coverage, whereas it is often readers who value features and specs over image quality, reliability and usability who are to blame. For example, video-oriented cameras with exceptional IQ but lacking IBIS are categorically dismissed as absolute failures by enthusiasts, who disdain tripods and gimbals. One filmmaker even confessed to relying on his lens’s optical stabilization when shooting on sticks because his tripod head was too flimsy. In actuality, far more harm is done by misinformed members of the internet community than by reviewers.
Henry Gentles writes in the OESHD forum:
I have the sigma 18 -35 which is sharp for shooting video and portraits but the CA when shooting a tree with leaves etc the lens is total crap, can’t do it at any aperture! The cheapo Canon 17 -40 f4 L lense craps all over it! I would have sold the 18 -35 but its so versatile for shooting room scenes in lower light but as a wideangle for stills, it’s unusable! Canon lenses don’t do that, not even the cheaper Canons! The older AI Nikons are the same, quality lenses, almost all of them! All these 3rd party ultra sharp lenses with multiple elements have serious trade offs. The Sigmas are the worst offenders, can’t recommend any except the 105mm and the 150mm which are superb and cheap.
I inquired why Sigma lenses were useless for shooting stills when chromatic aberrations are easily corrected for in most editing software. I also pointed out that the Zeiss Otus 50mm f/1.4 doesn’t suffer from chromatic aberrations, and neither does my favorite lens, the very sharp 23-element Fuji 50-140mm f/2.8, while acknowledging that distortions and vignetting are fixed by firmware when using the manufacturer’s system lenses. I added that I found the pervasive misconception that third party multiple element lenses with outstanding resolution are somehow inferior disturbing.
Henry Gentles responds:
This is common knowledge now actually. If you focus on a large tree from a distance to frame the tree, none of leaves will be in focus and at any aperture. You will think the leaves are moving but even when you increase the shutter speed same result, garbled leaves. It’s chromatic aberration, a design flaw due to the 14 elements etc. There’s a few videos on this on youtube but I can’t find them right now. Plus the 18-35 won’t focus using the outer focus points, you have to use centrepoint only. The Lens is complete junk unless you use centrepoint focus only. The new 50-150 1.8 they just released is even worse, it just doesn’t focus every 5 or 6 shots or whatever, which means unusable for a professional stills photographer. Totally unreliable auto focus. The Zeiss and the Fuji are not 3rd Party and are great lenses no doubt and cost a bomb, not sure your point?? The new chinese$2K Nikon 85mm has a similar issue to the 18 -35 due to all the elements, stick with the old one much better Lens and half the price.
There you have it: not only does Mr. Gentles evade replying to my statement about chromatic aberration being an issue of little importance (all tests of the Sigma reveal a minor to insignificant degree of chromatic aberration), he also seriously exaggerates the optic’s autofocusing inaccuracy and has the temerity to contend that Zeiss, which manufactures lenses for Nikon, Canon, Sony, Fuji and other lens mounts, is not even a third party lens manufacturer!
And here is a video that demonstrates that the with the MC-11 adapter, Sigma’s continuous autofocus outperforms both Canon and Zeiss glass on the Sony a6500, a result which surprised even the tester.
The Daejeon Chronicles 
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