Andy Westlake tests an intriguing lens that mixes extreme wideangle macro with shift capability
Laowa LX FX 15mm f/4 Wide Angle 1:1 Macro review: Resolution, shading and curvilinear distortion
The 15mm gives decent results in our Applied Imaging MTF tests, here on the full-frame Canon EOS 5D Mark III. Wide open at f/4 it’s pretty sharp in the centre, but the corners lag some way behind. They improve on stopping down, though, with the sharpest overall results at f/8. Stopping down further results in progressive diffraction softening, with f/32 generally best avoided unless extended depth of field is paramount.
With the lens’s small optical unit and wide view, it’s no great surprise to see quite strong vignetting at f/4, with 1.8EV fall off in illumination at the corners on full frame. This diminishes on stopping down, and by f/8 it drops to below 1EV, which is unlikely to be troublesome in practical use.
Not unusually for a wideangle, the Laowa 15mm shows rather pronounced distortion. It’s rather complex too, being of the ‘moustache’ type with strong barrel distortion towards the centre of the frame (and therefore in the APS sensor area) that’s re-corrected into the corners. This doesn’t matter for macro, but is undesirable for other subjects.