Janus asked: "Hello list ,stupid question, as its a long time sinse I read 'Langfords' , could someone explain why dirt on a ccd looks sharper with the lens shut down than wide open ?"
When lens is stopped down the light is passing through a smaller hole then giving sharper shadows. The distance from the dust to the pixel surface are prolonged by the alias filter. Quite like you have a softer shadow using at light with a soft filter 30 cm in diameter or covering it with black making a hole down to 5 cm. Best regards Vagn-Ebbe Kier =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
