Appendices
Figure B.2 A monorail camera offers the greatest variety and range of shift and pivot movements, which can be used simultaneously
Drop front means shifting the lens downwards, again parallel to the film, placing the lens axis below the centre of the picture format. Cross front involves shifting left or right, parallel to the film, placing the lens axis to one side of the picture centre. These three shift movements are achieved on a view camera by undoing locks on the front (lens) standard and sliding it a few centimetres up, down or sideways. On a monorail view camera front and back standards are identically engineered, so you can double the effect by moving them in opposite directions – for example shifting the back of the camera downwards when you use rising front. Standardlength bellows may not be flexible enough to allow much shift movement. With a view camera you can work more easily by changing to bag bellows instead (Figure 5.9). One or two rollfilm cameras (wide-angle shift cameras) offer shift movements by not having bellows at all. Instead (Figure B.1) two sliding plates are used and the lens has its own focusing mount. On small- or medium-format SLR cameras the body as such may not offer movements. Instead you fit a ‘shift’ or ‘perspective control’ (PC) lens. This has a special mount allowing the whole lens to slide a centimetre or so offcentre in one direction. The mount itself rotates, to allow you to make this off-setting give either upward, downward or sideways shifts.
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Note on lens coverage
Shift movements (or lens pivoting) tend to move the lens axis away from the centre of the picture format. You should only do this if your lens has sufficient covering power (Figure B.4) to continue to illuminate the entire picture area. Otherwise the corners and edges of the format farthest from the lens axis will show blur and darkening. Most good lenses for view cameras are designed with these movements in mind and have generous covering power. The usual range of lenses for medium- and small-format cameras cover little more than the picture area for which they are designed. Shift lenses are exceptional. Optically they must cover a much larger image patch. Mechanically too the back of the lens must be far enough forward to allow off-setting and pivoting without fouling the sides of the mount. Most shift lenses are wide-angle, typically 75 mm for 6 × 4.5 cm or 35 mm or 28 mm for 35 mm format. Using rising front
Effect. As you raise the lens the image shifts vertically too. The lowest parts of the subject no longer appear but you gain an equivalent extra strip at the top of the picture. Raising the lens, say, 1 cm raises the image 1 cm. But in most situations the image is much smaller than the subject, so this small shift alters the subject matter contained in your picture by several metres – far greater than if you raised the whole camera by 1 cm. Practical purpose. Rising front allows you to include more of the tops of subjects (losing an equivalent strip at the bottom) without tilting the