Lens review

Olympus Zuiko Digital 25 mm f/2.8

8. Vignetting

For a lens moderately fast, the ZD 2.8/25 has a significant falloff. This is the price you have to pay for the compact dimensions.

At maximum relative aperture the corner illumination loss is 31 % (-1.06 EV). On stopping down to f/4.0 its level decreases to 23% and by closing by one more stop it reaches 16%. Only by f/8.0 it becomes imperceptible (10%).

The results don't position the Olympus well when compared with other “pancakes”. The Pentax 2.8/40, which works on a significantly bigger 1.5x detector, had practically the same results.