On Thu 2001-12-06 (12:14), Frank Wajer wrote: > Hi, > > can anyone explain to me how a graduated filter works. I think that all > light from all points in the > scene go through the entire filter/lens so how can a graduated filter > darken the sky relative to the > (fore)ground.
So, if you put your finger in front of the lens, it won't be visible? You got an interesting idea. Put in fact although light from all points is transmitted to all directions, what you catch in the lens is the selected part directly to you, as a projection to the film area. Otherwise all you could take is some kind of continous color/gray would be banned on the film. True that anything in front of the lens can't be in proper focus - but the projection of its shape/color will be on the film (more or less sharp). It's just one of the miracles ot optics, hard to understand hundreds of years ago and still not obvious :-) Martin - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
