Re: rise or fall

[Andrew Fildes <afildes@xxxxxxxxxxxxx>]

The eye has two lens with no provision for shift - bobbing your head up and
down is as effective as waving the camera around. Shift adjusts perspective
- straightens up a building, widens a river, alters the plane of focus -
point of view shouldn't change and cropping is minor and incidental. Are
you confusing the effect of a shift lens, where there is movement between
lens elements, with the rise and tilt of a view camera where the movement
is between the whole lens and the plane of the film?

>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.
>>
>>