Archived posting to the Leica Users Group, 1998/01/22

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Subject: Re: [Leica] Re: shift bellows
From: Donal Philby <>
Date: Thu, 22 Jan 1998 16:38:19 -0800

> In a message dated 98-01-22 14:59:49 EST, you write:
> <<
>  > How can a lens that is designed to cover a 24x36mm format possibly cover
> that
>  > format when it is tilted and swung?
>  > Charlie
>  If you think about the cone of light from the back of the lens just
>  filling the frame of film, then imagine the lens farther away as it
>  would be on a bellows, the cone of light gets larger, but of course you
>  lose light according to the inverse square law.
>  donal
>   >>
> Of course you are correct, Donal. But using the lens at a greater distance
> means that you are focusing on a very close object. I guess I don't know why
> anyone would need tilts and swings for such a photograph. Others have
> commented on the use of the bellows for a 135/150mm enlarging lens. Of course
> they would cover far more area than needed.
> Charlie

We were discussing a bellows unit, so they won't even focus at
infinity.  But even so, having a tilt shift for a telephoto is handy to
get depth of field.  If you look at a current M6 brochure you will see a
picture of a bunch of uncompleted Leica bodies lined up.  This was shot
by Luis Castenada with an R7 and tilt/shift adapter and a viewcamera
lens.  Almost imposible to do otherwise.  Imagine shooting a field of
flower with a long lens, say a 180mm to get all that compression and
then being able to tilt the front and get everything in focus.  The 90
Canon is perfect for that.  I take my hat off to Canon for there three
T/S lens and would like to have all three.  A bellows with T/S help on
macros by helping shift the plane of focus to compensate for minimized
depth of field.  The shift works with the coin shot by letting you get
off axis to the camera sees light reflected off the coin and from a
position beside the camera so you can control the reflection.  Hard to
describe. But try it with out bellow just by tilting camera and playing
with a reflector card.  With shift you accomplish this while keeping
perspective correct.

Often in corporate settings I would like to have a 35mm T/S lens to do
people and computers.  By use the tilt as a swing I minimize DOF needs,
thus cutting computer screen burn in time down to 1/4 second, say,
instead of 4 or 8 seconds, while keeping in focus what I want in focus. 
Instead of setting strobes at f/11, say, I could shoot at f/5.6. Better
for impatient models.  

Mo' better.

- -- 
Donal Philby
San Diego