"The Joys of Wide Open Apertures
In the Old days it was a recognized photo technique to stop down the lens aperture to improve picture quality. In those times lens performance wasn't what it is now, and film performance and flatness also left much to be desired, so stopping down the lens was the sensible thing to do. Perhaps the image of those days is still with us, because many people still seen to think the lens has to be stopped down for satisfying results. But times have changed. Today's lenses are outstanding performers. Especially with lenses like this Zuiko 250mm F2 that makes use of special new types of optical glass, you can get astonishingly sharp images even at wide open apertures. If you can get really sharp images at wide open apertures, except for the narrowing of the depth of field the advantages are extraordinary. Most important of all is that you can use high shutter speeds, or benefit from the superior color rendition of lower speed films."