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Perspective correction for regular photo
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If the girl were closer to the building I suspect there would be no objectional distortion. As she is so much closer, the perspective on her is actually dfferent that that of the building. "What can you do with the view camera that the tilt/shift can't do?" Here's a very abbreviated summary. The most flexible (but least portable) view cameras are built around a "spine" that is called a monorail. Can be square or circular in cross section. On either side of the tripod mounting fixtue are two sliding units. One has a clip to hold a lens mounted on a board; the other has a clip that holds whatever it is that holds the film. They both also have a clip that holds the light-proof "body" of the camera. This "body" needs to be flexible for reasons I'll get into later; normally this is a pleated construciton similar to an accordian bellows, though for wide angle optics it can be more shapeless so movement is not restricted. Focussing is accomplished by sliding the two standards closer together or farther apart. Both the lens and the film standards are articulated in just about every direction in 3 dimensional space. Both can move side to side ("shift"), up and down ("rise and fall"), around the vertical axis ("swing") and around the horizontal axis ("tilt"). Different manufactures implement the nodal point of the tilt differently and claim superiority, but that's the basic range of movements. Understand that view camera lenses are designed to project a larger image circle than the size of the film. Let's make up numbers: say you have a camera that takes 4x5 inch film, and a lens that projects an image into the camera body of 10 inches in diameter. This means you can move the film around in that image circle. What? Okay - you point a camera at a building and don't get the top. You don't want to point it up for fear of convergance. You keep the camera (or more accurately, the FILM PLANE) parallel to the buiding but RAISE the lens (or LOWER the film) and now you have shifted the part of the image circle that has the top of the building so that it is projected onto the film. Another example. Let's say I have to take a picture of a mirror in a rectangular frame. I don't want to be reflected in the mirror, so I have to stand to the side. But I don't want the geometry of the mirror to be distorted. I can stand to the side and SHIFT the lens or film standard so the mirror is centered on the film and the geometry is preserved. All this assumes a lens with infinite coverage which in the real world never happens. Sharpness and exposure falls off at the edges of the circle too (it is possible to move the film outside the area of the image circle - not good!) so there are always compromises. That all has to do with maintaining geometry. In terms of focus it is possible to get a plane of infinite depth in focus with the lens wide open using tilts or swings. The classic example is the railraod track stretching to the horizon. With a fixed body camera you are reliant on depth of field (a small aperture) to keep it sharp near to far. With a view camera you can tilt the lens and/or the film standard and have that PLANE the railroad tracks lie on dead sharp wide open. Note I said "PLANE" - you still need a small aperture to get the telephone poles that are perpendicular to the plane of focus sharp! The price for all this flexibility is being bound to a tripod and doing your focus/composing under a black cloth to block out ambient light while looking at the image upside down! That's a superficial summary of whata's different about a view camera from a fixed body camera. Helpful?
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