This has come up before, and I didn't believe the answer offered then. But
it has taken me awhile to work out why...
It's my understanding that the 83 degrees coverage is *not* the image
circle, but the field of view when the len is at maximum shift.
It isn't that the shift lens itself can defy the laws of optical physics,
but that when the lens is shifted, the field of view is no longer
perpendicular to the lens axis and perpendicular to the film plane (but
still parallel to the film plane). Therefore, the greater the amount of
shift, the smaller the angle between the lensaxis and film plane, and the
greater the angle of view.
It's the laws of trigonometry.
Piers
-----Original Message-----
From: owner-olympus@xxxxxxxxxxxxxxx [mailto:owner-olympus@xxxxxxxxxxxxxxx]
On Behalf Of Geilfuss Charles
Sent: 13 October 2003 19:19
To: 'olympus@xxxxxxxxxxxxxxx'
Subject: Re: [OM] Re: 35 Shift
Thanks for clarifying my misinformation Walt. I guess those Laws of Optical
Physics can only be bent not broken.
Charlie
-----Original Message-----
From: Walt Wayman [mailto:hiwayman@xxxxxxxxx]
Sent: Monday, October 13, 2003 2:12 PM
To: olympus@xxxxxxxxxxxxxxx
Subject: Re: [OM] Re: 35 Shift
Those numbers, while not intentionally misleading, are still often
misleading. The "field of view" of the 35mm shift is 83 degrees,
but that refers to the image circle around which you may wander in
shifting the lens while composing the final shot, which will
cover -- anyone? anyone? -- yes, 63 degrees, like a normal 35mm
lens.
Just to be sure, I have, moments before writing this, compared the
field of view of a 35 shift with a 35/2. They are identical.
Walt _____________________________________________________________
"Patriotism means being loyal to your country all the time
and to its government when it deserves it." -- Mark Twain
---------- Original Message ----------------------------------
From: Geilfuss Charles <Charles.Geilfuss@xxxxxxxxxxxxxxxxx>
Reply-To: olympus@xxxxxxxxxxxxxxx
Date: Mon, 13 Oct 2003 12:59:59 -0500
>Greetings Peter,
>Sounds like a great trip and I look forward to seeing some of your
>scanned images. Regarding the 35 Shift: mind you I've never actually
>used one of these lenses, but according to the Unofficial OM Sales Info
>File, the 35 Shift has a practical field of view of 83 degrees which is
>more akin to a 24mm lens instead of the usual 63 degree field of view
>of a typical 35mm lens. You may find it more to your satisfaction than
>you realise. Another plus, it's about one third the cost of the rare
>and lofty 24 Shift.
>
>Charlie Geilfuss
>
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