Yeah, you only need a larger image circle than the film if you want to use movements that displace the image circle at the film plane. These include rise/fall, lateral shift and front tilts and swings. Back tilts and swings don't move the center of the film from the optical axis of the lens, so not much coverage is needed for those.I'd call a 200mm IC "significantly larger" than 4x5 film. But the IC does NOT necessarily have to be "significantly larger" than 4x5 film. I have two lenses that are "barely" larger than 4x5 film. That's a limitation for shifts & rise/fall -- not so much for swings & tilts. And I have lots of macro lenses with image circles much smaller than 4x5 film -- when focused at infinity, which is NEVER. How bout 12.5mm?
The common terminology obviously long predates me, but in my head I really divide it into two movements--parallel movements and angular movements, then I further subdivide angular movements into front and rear angular movements. The helps my brain compartmentalize them, but I know I need to translate into the common usage when talking to others about it, since my terminology isn't known beyond me, but my thought goes like this:
- parallel movements just allow you to select what part of the image circle you are cropping to. front and rear parallel movements are fully "transitive" (this is really a misuse of this mathmatecal term, but it helps me) in that movement X on the front is identical to movement -X on the rear.
- front angular movements place the plane of focus as well as the zone of apparent focus (i.e. the depth of field) at an oblique angle to the film plane.
- rear angular movement also allow you to place the plane of focus at an oblique angle but also changes the geometry of the image, like converting a rectangle to a trapezoid. Because of the impact on the geometry angular movements are not "transitive".
I understand that in the mechanics of most large format cameras the hardware that enables rise/fall is different from the hardware that enables left/right shift and is probably why the two movements got separate names, but as AgX points out, on 35mm perspective correction lenses, they are usually implemented as a single mechanism--a rail that lets you off-center the lens by a certain amount, and a ring that lets you angle the the "shift" in any direction. To me shift, rise and fall are all the same function and it helps (me) to understand them that way.
Books on large format photography such as Simmons's "Using the View Camera" or Stroebel's "View Camera Techniques" typically have an entire chapter devoted to the effects of front and back movements, with illustrations. In both of these books, the illustrations include photos of a set of children's wood cubes with letters, so that you get a sense of how the movements can shift both perspective and focus.
When you have questions about the effect of movements, I recommend looking at a photo-heavy medium such as one of these books. Words can only do so much. I don't know of a website that has as comprehensive a set of illustrations.
Yeah, you only need a larger image circle than the film if you want to use movements that displace the image circle at the film plane.
Doremus
Raise is up.
Shift is right or left.
Well, I just looked into a British textbook on camera movements I got.
No mention of "shift" at all... instead "cross front" is used.
Instead of "swing" "vertical swing" is used.
Instead of "tilt" the term "rotating" is used.
So terms not only varied by language, but also between countries of same language. And yes, it is most confusing. Thus my engineering approach above.
AgX,Different terms are used...
(in translation)
Linhof
high adjustment
low adjustment
lateral adjustment
tilt
parallel shift (high & low)
lateral shift (left & right)
base tilt
central tilt
swing around vertical axis
Plaubel
parallel adustment (used for all kinds of shift)
swing (used for all kinds of shift)
Vielen Dank! Alles sehr logisch.Verstellung, Verschiebung
Neigung
Schwenkung, Verschwenkung
Verstellung is used for shift, but also is a superior term meaning movement in this context. Neigung is obvious, Schwenkung though ambiguous.
You Americans... be prepared to look beyond your horizons...
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