Sharpness at 18mm

For this review, the sharpness test is carried out by photographing a real-world sample, rather than a test chart. The Leica 18mm f/2.8 pancake lens was mounted on a Leica CL, 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 18mm

At the centre of the frame, sharpness is very good at the widest aperture of f/2.8, but is even better when you get to f/4.0. Sharpness is excellent up to f/11, where it drops off a little. It is softer again at f/16, but still acceptable when viewing at normal printing sizes. At the corners, the lens is sharpest between f/5.6 and f/8, but is still sharp at the other apertures.

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