Sharpness at 21mm

For this review, the sharpness test is carried out by photographing a real-world sample, rather than a test chart. The Leica Super-Vario-Elmar-SL 16-35mm f/3.5-4.5 ASPH was mounted on a Leica SL, which was in-turn mounted on a sturdy tripod. Exposure delay was activated to prevent camera-shake. Any changes in tone you might see across the crops are due to natural light changes during the shooting session.

The full frame at 21mm

At 21mm, centre sharpness is very good at the widest aperture of f/3.8, rising ever so slightly when you get to f/4.0. The sharpest results can be seen between f/5.6 and f/8. From f/11 a little more softness starts to appear, becoming softer again at f/16, before becoming the softest at f/22. At the edges of the frame, the sharpest results can be seen between f/4 and f/8.

Aperture	Centre Crop	Edge Crop
f/3.5
f/4
f/5.6
f/8
f/11
f/16
f/22