Sharpness at 8mm

For this test, the Olympus M.Zuiko Digital ED 8mm f/1.8 Fisheye Pro lens was attached to an Olympus OM-D E-M5 Mark II camera, which in turn was mounted on a sturdy tripod. The self-timer was used in order to avoid any vibrations that may result from tripping the shutter. Slight tonal changes are due to slight changes in natural light during the session.

The full frame at 8mm

In the frame centre, the lens is commendably sharp wide open, and reaches excellent levels of sharpness at f/4. Peak performance is achieved in the f/4-f/8 range. At the f/11 setting the lens is still very sharp but f/16, while usable, is starting to show the effects of diffraction rather obviously. The f/22 setting is best avoided. The corners suffer from light fall-off wide open but are otherwise quite sharp – very sharp for such an ultra-wideangle lens –, and follow a similar pattern to the central area as we go through the aperture range.

Aperture	Centre Crop	Edge Crop
f/1.8
f/2.8
f/4
f/5.6
f/8
f/11
f/16
f/22