Re: rise or fall

[ralph fuerbringer <rof@xxxxxxx>]

if moving your head up or down a foot or so doesn;t significantly change the
angle of view how can an inch or two do it  with a lens, an inferior
subsstitute for the eye? no, what it does is place on the negative  the
desired part of the larger image available with a lens covering
significantly more than the format. a shift is a cropping device, no more.no
less. if you had the whole image circle formed by the lens a shift of a foot
wouldn' amount to an anthill.
-- rof


----------
>From: zxiong@xxxxxxxxxxxxxxxxxxxxxx
>To: panorama-l@xxxxxxxxxxxxxxxxx
>Subject: Re: rise or fall
>Date: Mon, Feb 22, 1999, 11:12 PM
>

>
> I think a little optical illustration may help.  I hope this will display
t> properly in plain text mode.
>
>
>      Scene                 lens         image on film (upside-down)
>
>        ___
>         |
>         |
>    shift-up view                               ---
>         |                                       |
>         |                                 shift-down image
>        ---                                      |
>         |                                      ---
>         |                   /\                  |
>     no shift               |  |            non-shift image
>         |                  |  |                 |
>         |                   \/                 ---
>        ---                                      |
>         |                                 shift-down image
>         |                                       |
>   shift-down view                              ---
>         |
>         |
>        ---
>
>
> In one word, shift changes the angle of view.  It has two functions.
> 1, raise/lower the horizon on film; and 2, provide a higher/lower angle of
> view without tilting the camera so that the object (such as building) and the
> focal plane (film) remain parallel and thus vertical lines stay vertical on
> film (not converging lines which you'll get pointing your camera up).
>
> One good example is that when you shoot with a wide angle lens, you can pull
> in a toll building by stepping backward a few steps, not by climing a ladder.
> With a normal lens there may not be enough room for you to move back.
> Think shift as changing to a wider angle lens and you capture only part of
> the image of that wider angle.
>
>