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Comparison with Sony Sonnar T* FE 55 mm F1.8 ZA No reservations recommending this lens. That said, if you can spend extra time processing out the axial CA in post, don't mind onion-ring bokeh in out-of-focus highlights, aren't bothered by coma and don't need the extra isolation or light-gathering capability of F1.4, the 55/1.8 is a compelling alternative that is lighter and cheaper, while offering smooth background bokeh and impressive, if not necessarily much greater, sharpness wide open and faster AF.
Comparison with Sony Sonnar T* FE 55 mm F1.8 ZA -) Both wide-open, the 55/1.8 out-of-focus rendition is smoother even when compared to the 50/1.4 ZA when the background is close to the subject. Whenever the background is further away, the advantage goes to the faster lens.
-) The 50/1.4 is much better corrected for CA and LoCA.
-) The 50/1.4 ZA and FE 50/1.8 ZA are very comparable wide-open in terms of sharpness but the 50/1.4 has higher micro-contrast.
-) The 50/1.4 at f/1.7 is noticeably sharper than at f/1.4.
Admiring Light The only two things that are bad about the lens: it’s quite big, and it’s quite expensive. If you can get past those, there’s absolutely nothing left to worry about. Optically, this is the finest 50mm lens I’ve ever used and is among the finest lenses of any focal length I’ve ever used. It’s exceptionally sharp across the entire frame right from f/1.4 [...]. The bokeh is excellent and it controls almost all aberrations extremely well.
The image quality is absolutely stunning. Wonderful contrast, razor like sharpness, smooth bokeh. I can’t find anything to complain about in terms of image quality. In terms of build, I wish it had a focus hold button and unfortunately, the focus is not entirely completely silent. [..] Thought, many enthusiasts bought into the Sony system in order to reduce their system size. The size of the 50mm F/1.4 defeats this goal.
It is just the kind of lens that Sony FE needs – a premium option that rivals (and even surpasses) the best available on competing systems. It has a premium build, premium mechanics and features, and premium optical results. It is expensive, yes, but it surpasses the build, handling, and real-world performance of the Sigma 50mm f/1.4 on the lower price point end, [...] though big and heavy.