</span><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (David A. Goldfarb @ Feb 22 2003, 11:48 PM)</td></tr><tr><td id='QUOTE'>If you can't carry a camera with movements, you can always tilt the easel in the darkroom to correct convergences.</td></tr></table><span class='postcolor'>
No David, you can't always. In the darkroom, you can only correct converging lines in one level. If your scene does have converging lines in several levels, you must shift the lens at exposure time. The perspective ratio between foreground and background objects is determines by the focal length (the picture angel) of the shooting lens. The resulting two-dimensional image lacks the ability to apply selective perspective corrections. The shorter your shooting lens, the more apparent will this be.
The corresponding darkroom technique for shift lenses is not Scheimpflug Distortion. It is a pair of scissors for an image taken with a wider lens.