The camera used for these pictures was a 35mm Widelux. This produces negatives 59mm long and 24 mm high. The lens pivots around its centre during exposure, projecting its image through a slit onto the film which is curved around a segment of a circle with the same centre. The 26mm lens may not seem particularly wide-angle, but because of the elongated format and curved film plane records a horizontal angle of view of 130 degrees.
The curved film plane gives a constant lens to film distance over the whole negative unlike a normal camera. This avoids the normal distortion of ultra-wide lenses which results in a stretching of objects towards the edges of the frame, but results in a characteristic curving of any non-vertical straight lines which do not run through the centre of the frame. For normal use it is essential that the camera is used upright, as any tilt results in a curvature of the horizon. A spirit level is built into the camera . The 2.5 to 1 aspect ratio, the ultra-wide angle of view and the curvature effects of the camera impose a particular discipline on composition which I find stimulating.
The camera has shutter speeds 1/15, 1/125 and 1/250, although the total time of exposure is several times greater than these as only a slit of film is exposed at any instant. Hand-holding is possible at all speeds, but easier at 1/125 or 1/250. The minimum aperture is f11 and the camera has a fixed focus.
This camera was appropriate because of its:
suitability for recording linear structures (or non-structures);
circular movement used to record the circle of the meridian.