Movements

There are three types of movement, these can be applied to both the front and rear standards:

• Focusing
• Parallel Displacement
• Rotational

Focusing

Front Focus

- movement of the lens along the Z axis - gives a change of focus together with a change of magnification.

Rear Focus

- movement of the rear standard along the Z axis - gives a change of focus without a change of magnification.

Parallel Displacement

Rising Front

- movement of the lens along the Y axis.

Shift or Cross Front

- movement of the lens along the X axis.

Rise and Shift to the Back

- movement of the plate (rear standard) along the Y and X axes.

Rise and shift movements to the lens or plate simply positions the plate within the image circle projected by the lens.

A common application is for rising front to be used to exclude excessive foreground from the image. The amount of movement that is possible is limited by the size of the image circle usually expressed as the angle of view of the lens.

Rotational

Tilt and Swing to the Back

- rotation of the plate about the X and Y axes respectively - changes the image shape and the plane of focus. Used to correct distortion introduced when the camera is tilted (perspective control) i.e. when the camera is tilted to include the top of a building the back is tilted to be parallel to the building. Also used to position the plate for focus on objects at different distances.

Tilt and Swing to the Lens

- rotation of the lens about the X and Y axes respectively - tilts the plane of focus and depth-of-field zone.

Rotation of the Plate

- rotation of the plate about the Z axis - positions the plate within the image circle projected by the lens - changes the orientation of the image i.e. landscape or portrait format.

Mechanically tilt and swing can be attained by pivoting the standard at its base - base tilt - or from the centre - centre tilt. The effect is the same but centre movement is easier to use.

When the lens is tilted to change the plane of focus the plate should also be tilted so that the three planes - object, lens, image intersect in a line. This was described in a patent by T. Scheimpflug (British Patent 1196 of 1904). The apparatus described in the patent was for removing distortion when reproducing plates. Scheimpflug was anticipated by Jules Carpentier (British Patent 1139 of 1901) when describing enlarging equipment. The immediate effect on the photographic public of Scheimpflug's patent was not great.

In the Past

The terminology used to describe these movements has changed over the years. Previously tilt was known as swing, vertical swing or swing about the horizontal axis. Swing around vertical axis was usually referred to as side-swing.

Rising Front

This was introduced in the 1840s though not common until a few years later. Sometimes known as 'sliding front' or, when combined with a cross front movement, 'Double action sliding front'. A rising front was fitted to most stand cameras (field, tailboard, etc.) from the 1880s onwards except for the very simplest. It continued to be fitted not only to 'Hand and Stand' models but also to reflex and the small metal-bodied hand cameras that were coming on the market. On better models it was operated by a rack and pinion or worm screw action, on others, simply a friction slide. Much emphasis was placed in camera advertisements on the amount of rising front available (e.g. Newman & Guardia), showing it to be in common use by amateur photographers using non-specialist equipment.

Where a rear focusing screen or reflex camera was used the amount of rise could be seen on the screen, on other cameras the view-finder might be calibrated along with the rising front setting (e.g. Sinclair Una, N&G Sibyl) or be connected to the rising front and so automatically adjusted (e.g. Adams Identoscope).

The image on the right shows a view-finder fitted to a hand camera. The amount of rise is found by lifting the lens of the finder, the setting is then transferred to the camera lens.

Cross Front

This was fitted by at least the early 1850s e.g. Ottewill's Registered Camera. Its purpose was, in most cases, to provide a rising front movement when the camera was turned on its side i.e. a reversing or revolving back was not fitted. Cross front is usually present on tailboard cameras where the large flat front is ideally suited, it is less common on field cameras.

Cross Front could also be used to provide lens separation when taking stereo photographs, for this the lens panel was made exceptionally wide and a large cross movement provided.

Rise and Shift to the Back

These movements are not found except on specialised studio, process cameras and later monorails.

Tilt and Swing to the Back

These movements are found on studio cameras as early as the 1840s. Cameras fitted with tilt and swing are shown in Knight's catalogue (1853) and described in Willats's catalogues of 1849 and later. The 1849 catalogue claims it was introduced by Dr Leeson in 1845.

Tilt was recommended for two purposes:

• To bring foreground objects into focus when photographing landscapes and when taking portraits to bring the face and knees of the sitter into focus. This was an important consideration at a time when large aperture, long focus, lenses with shallow depth of field would have been used for portraits.
• Tilting back was also used when the rising front was not sufficient, the camera would then be tilted upwards and the tilting back used to bring the plate vertical.

The amount of tilt was found simply by trial and error. When photographing a landscape for instance, the image was focused on the middle distance, the back was then tilted and the foreground focused, if this required the lens to be moved away from the plate the back needs to be tilted further.

Tailboard and some folding bed cameras were often fitted with a centre swing to the back with the horizontal axis somewhere near the image plane. Two methods were commonly adopted:

• A small frame carrying the plate holder was added which could be pulled away from the rear standard. The frame was able to pivot about the horizontal and be locked in position by slotted plates at the top of the frame (fig. 60).
• The rear standard could be cut away at the top and bottom allowing the frame to pivot about the horizontal (fig. 60a).

Limited side swing was sometimes provided by allowing a degree of movement when clamping the rear standard to the baseboard. On some models a dedicated side-swing movement was added controlled by a rack and pinion (fig. 61).

Field and folding bed cameras had base swing permitted by the way they collapsed when being closed. Dedicated side swing was available on some models by mounting the frame carrying the plate on slotted plates e.g. Sanderson and Gandolfi cameras (fig. 77c).

Tilt and Swing to the Lens

Tilting Front was possible on some Kinnear pattern cameras as early as 1860. On later field cameras base tilt was often possible by the way they collapsed when being folded. On Sanderson cameras (1895) tilting front on the axis of the lens panel was provided and advocated by Sanderson as a better option than tilting the camera and using the tilt back.

An interesting camera was produced and patented by John Cooke Bourne in 1855 (BP 674), this allowed the lens to move in a curved slot the radius of which was the same as the focal length of the lens. On a Shew Eclipse strut camera of 1891 (British Patent 15657) centre tilt of the lens was provided for use in place of a tilting back.

Lens movements in these early years were seen as an alternative to using rising front or tilting back movements rather than changing the plane of focus. Also, at a time when setting up a camera on a tripod was time consuming and where a restricted location limited the camera view-point, small adjustments to the lens positions would have been used to compose the photograph.

References & Notes