Andy Westlake tries out Sony's latest premium fast prime designed for Alpha 7 users, the Sony Planar T* FE 50mm f/1.4 ZA
Sharpness, shading and curvilinear distortion
At first sight these graphs may look unremarkable, with central sharpness exceeding the corners at all apertures, and the sharpest results around f/2.8-f/5.6. But the actual numbers from our Applied Imaging MTF analysis are staggering; this lens is sharper in the centre at f/1.4 than most others manage at their very best. Remarkably, even in the corners it’s as sharp as most other lenses are in the centre. This is impressive indeed.
Inevitably for a full-frame fast prime, vignetting is readily visible, with our tests revealing 1.5 stops of fall-off in the corners of the frame at f/1.4. The smooth fall-off profile means that it’s not objectionable, particularly in comparison to some zooms that show sudden brightness drops in the corners. Vignetting drops to less than 0.8 stops at f/2 and effectively disappears altogether at f/2.8.
Our tests reveal just a hint of pincushion distortion, but it’s not visible in normal use. Unlike with many CSC lenses that rely on software compensation, the optical correction is almost complete. It’s possible to apply some additional correction in-camera, but there’s little need.