There are two things we look for here when shooting this chart; the first is the highest resolution possible, and the second is each lens’ edge-to-edge sharpness. Unfortunately we can’t change the aperture settings on the cameras and they’ve each elected to shoot wide open, where the highest possibility for corner softness is.
That said, the Apple iPhone 5S turns in a solid performance, scoring approximately 1800 LPH horizontally and vertically. Just as we found in our smartphone shootout in the June issue of HWM, the 5S’ lens is remarkably sharp from corner to corner.
It’s remarkable because the 5S is ‘just’ a smartphone, and there are digital compact cameras as well as some interchangeable lenses which can’t achieve this degree of consistent sharpness while shooting wide open. It's also impressive how little barrel distortion there is; a little can be expected with wide-angle lenses (see the Z1's below) but the 5S has little to none. At ISO 80 however, the 5S is introducing some muddiness into the grey areas, but the black zones remain noise-free. There is also some appearance of moire in the fine lines where the small sensor probably can't resolve detail.
The Sony Z1’s full-resolution 20MP shot of the resolution chart is troubling, and a sign of trouble to come. The Z1 has a higher resolution score, 2200 LPH horizontally and vertically. But there is a noticeable amount of noise and image artifacts, even at ISO 64. The overly aggressive image processing even introduces odd hexagonal shapes in the 3600 LPH curve which flows into the center - ordinarily when a camera can't result that fine it'd just collapse the area into a grey mess.
Aside from being sharp in the middle, there is also noticeable softness in the lens’ capture (look at the two vertical bars).
The Z1’s 8MP capture in Superior Auto reduces resolution, and also drops the appearance of noise and image artefacts, but the lens’ corner softness remains.