Re: how does a graduated filter work?

2001-12-06 Thread Alan Chan

Oh man, you are asking a question about physics. I am lost...

regards,
Alan Chan

>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.
>
>Frank


_
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp
-
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 .




Re: how does a graduated filter work?

2001-12-06 Thread Johan Schoone

Frank Wajer <[EMAIL PROTECTED]> 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.

The distance between the filter and the optical center of the lens
(which is behind the front element) does the trick. If you use an
extreme wide-angle lens at small aperture you get a pretty sharp clear ->
coloured transition.

Question: What filter type do you (plan to) use?
-- 
http://members.chello.nl/~j.schoone\\|//
Registered Linux user #78364 - The Linux Counter - http://counter.li.org
Assume nothing, expect anything.
-
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 .




Re: how does a graduated filter work?

2001-12-06 Thread Martin Trautmann

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 .