From: bjs@uts.amdahl.com (Barry Sherman)
Newsgroups: rec.photo
Subject: Re: Tilt and Shift.  How useful are they?
Date: 10 Sep 92 18:56:53 GMT
Followup-To: rec.photo
Organization: Amdahl Corporation, Sunnyvale CA

G. Hugh Song writes:

>We know they use this feature for architectural works.  So,
>Large-format camera owners!  Especially field camera owners!
>How often do you use this feature for landscape works?  

Nearly every shot.  Let's not forget that large format cameras use longer
focal length lenses.  90mm is very wide angle (equivalent to between 24mm 
and 28mm in 35mm camera lenses.).  210 is equivalent to an 80mm lens for
35mm.  Longer lenses produce greater magnification (which is why they're
used) which implies less depth of field which implies that you gotta
do something to achieve DOF.  Tilts and swings are the answer, combined
with stopping the lenses down.

>I think that
>greater depth of focus can be achieved with these field cameras than
>with usual medium format cameras with normal lenses.   

Er.  Possibly.  Since I use 4x5 but not medium format I hesitate to 
state anything positively.  But I think this is true in many cases where
the tilts/swings can be used.

>At what focal 
>lengths are they really useful?   

Most all.  After all, that 90mm lens doesn't give any more DOF on a 
4x5 than it does on a 35mm camera, even though it's wide angle on 4x5 and
mildly long on 35mm.  And 90mm lenses aren't know for great DOF.

>Is there any difference in the way tilt 
>and shift work between wide-angle lenses and telephoto lenses? In terms
>of tilt angles, so to speak.  

Not really.  They're more difficult to use with wide-angle lenses since
the bellows is compressed because the lense is closer to the back due to the
shorter focal length and can interfere with movements.  A non-pleated
"bag" bellows is a nice accessory to minimize this.

>The lens should be especially free from 
>vignetting, shouldn't it?  

It's really not an issue of being "free from vignetting".  All lenses
produce a circular image.  The issue is how large is the image.  In a 
view camera this image must be considerably larger than the film size in
order to permit using movements.  The larger the image circle (commensurate
with a sharp image) the more desirable the lens.  Short focal length lenses
tend to produce smaller image circles than do long lenses.  Thus the 
movements can be used more with long focal length lenses.

>Do usual telephoto lenses suffer from 
>vignetting when used with tilts?

See paragraph immediately above.

This all probably seems complicated and arcane.  It's not!  There are 
several good books on view cameras (including sections of Ansel Adam's
_The Camera_) which make things more clear than I can here.  Also, renting
one and a couple of lenses and playing with it would make things clear
also.

Barry

>
>Thanks a lot.
>
>	Hugh


-- 


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| Barry Sherman, Amdahl Corp.       | "Any fool can face a crisis - it's     | 
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|                                   |  out." - Anton Chekhov                 |
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Newsgroups: rec.photo