Folding
For a list of folding cameras, see Category: Folding.
A folding camera is a camera with bellows that can be folded to occupy less space. Not all bellows cameras can be called folding: a monorail view camera has bellows, but it cannot be folded and instead provides flexibility for "movements" (as well as allowing some compression for relative ease of transportation). The more sophisticated press cameras (like the Busch Pressman) are both in one: bellows camera (for photographical flexibility) and folding camera (for compactness). That's because the unfolded bellows' geometry can be changed for optimization of the image plane. The better press cameras and some other sophisticated amateur folders have that flexibility that allows making proper reproduction and architecture images.
Normal folding cameras more or less perfectly force the lens board and image plane to be parallel, and the lens and image frame to centre on an axis perpendicular to these two planes. This reduces the function of the bellows to ordinary making small those cameras for easy camera placement in one's pocket or luggage.
The scope of the term folding camera is unclear. While there is no dispute that the Agfa PB 20 is a folding camera, cameras such as the Plaubel Makina that employ bellows and hinges to collapse when not in use, but for which neither the lens assembly or its cover is hinged in relation to the body, are regarded by some people as strut folding cameras, but are regarded by others as not folding cameras.
Putting aside strut folders (if they are indeed folders), we can divide folders into two. A minority, exemplified by the Voigtländer Vitessa, have "barn doors": a symmetrical pair of doors. The others have a single door. A distinction is sometimes drawn between whether the bed hinges vertically or horizontally, but other than for square format (e.g. 6×6) cameras, normally only held in one way, this distinction too is ambiguous as it is not clear what "vertical" and "horizontal" mean.
There have been folding cameras in all kinds of format, from 18×24 mm to at least 18×24 cm.
| common folding cameras | special folding cameras | |||
 a folding bed camera ... |
 a strut folding camera ... |
 modern Polaroid, unfolded |
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 ... unfolded, hinged lid flapped aside |
 ...unfolded |
 press camera, folded |
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