On Jun 4, 2012, at 17:31 , J.C. O'Connell wrote: > In theory a perfect lens would be sharpest wide open, so a really good lens > would be sharpest close to wide open. If it takes 4 or 5 stops to sharpen up > a lens, its probably not that great. As for good rules of thumb, I find f5.6 > or f8 to usually work pretty damn good....
If a kens is designed to be at it's optimum wide open and becomes less sharp as you stop down - why bother with an aperture at all? DOF?? - use another lens. Joseph McAllister Pentaxian -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
