Although it was as far back as 1894 that the first commercial moving picture camera appeared in Great Britain, the years have not produced many marked departures from the design as elaborated by Paul. Time has proved his plan to be the most reliable and efficient. But as the art has developed and many minds have been concentrated upon the apparatus, it has undergone modification and improvement in minor details, all tending towards greater excellence in the ultimate results.

Paul’s camera was a small wooden cabinet, measuring only about six inches each way. It contained merely the requisite intermittent mechanism to bring successive depths of the film before the lens, and the tube to enable focussing to be carried out easily from the back, and in such a way that it was impossible for the film to become fogged when the tube was left open inadvertently.

This instrument was a model of simplicity, compactness, portability and convenience. The film was carried in separate dark boxes of a size to hold 160, 350, or 700 feet, according to requirements. These were detached from the camera itself, the box of unexposed film slipping into a device on top of the camera in such a way as to ensure a light-tight joint, and locked into position to prevent accidental detachment. From this box the film was led through the camera mechanism, past the lens and into a second box, similarly detachable. The apparatus therefore was resolved into three main parts—the camera, and the unexposed and exposed film boxes.

The modern cinematograph camera is completely self-contained; the film boxes are incorporated within the case that carries the mechanism for moving the film forward. Further improvement is hard to imagine. Bulk and dimensions are reduced to the minimum, with, at the same time, the maximum of efficiency.

The cinematograph camera, unlike most machinery, is called upon to face exigencies, and to perform exceedingly hard work under the most adverse conditions. To-day it may be in the broiling sun on a tropical desert; a few weeks hence it is plunged into the extreme cold of the Arctic circle; a little later it is well-nigh submerged in a reeking swamp or vapour bath. Such varying conditions subject the material and workmanship of the instrument to a supreme ordeal. Consequently the greatest care has to be exercised in the selection of material, the fashioning of the component parts, and their fitting together. Only the best seasoned mahogany can be utilised to withstand the strains of warping, shrinking, and expansion under extremes of heat and cold, and climatic fluctuations.

In the ordinary stand camera used for still-life work, there is a bellows which can be racked to and fro to enable the subject to be focussed sharply upon the ground glass screen. The cinematograph camera has no bellows, and there is no fixed screen for focussing purposes. In the simpler and cheaper cameras, suited to amateur use, the operator is not troubled with focussing details at all, the lens being of a fixed focus as in certain types of snap-shot hand cameras; but in the more expensive instruments, designed for producing the finest classes of work, focussing facilities are incorporated.

In order to grasp the operation of the camera, we will open the hinged door with which it is provided on one side, and gain access to its interior mechanism. It would be invidious to select any special type of camera, inasmuch as they all work more or less upon the same principle, the differences being only in minor details.

By reference to the illustration it will be seen that the apparatus is in three main parts. The rear half of the cabinet carries two square compartments, A and B, one above the other. These are for the two film boxes, A carrying the unexposed, and B the exposed film. It will be noticed that the cinematograph works upon the system of roller photography. Indeed, it might be described almost as a semi-automatic application of the familiar snap-shot camera using roll-films.

The lens is set centrally in the front face of the camera, and carries a screw, by means of which focussing is effected by moving the lens itself to and fro a short distance within a horizontal tube, which corresponds to the bellows in the ordinary camera. In addition it is fitted with stopping facilities working upon the well-known Iris principle, whereby the size of the aperture may be increased or diminished by a rectilinear movement. Behind the lens, and on a line with it in the interior, a tubular connection C extends transversely through the width of the camera to the rear, and through the outer wall to the external face of the case. This is the focussing tube, into which the operator looks through the small circular orifice E in the back face of the camera, known as the eye-piece.

The mechanism by which, with an intermittent motion, the film is jerked forward three-quarters of an inch after each exposure, is of the simplest design. The film as it issues through a narrow slit from the unexposed film box A, is passed under a small guide roller, having a smooth face. Thence it passes upwards over a second roller and down under the sprocket wheel, the teeth of which engage with the perforations in the edges of the film, and thus guide it forward. As the film passes upwards from the sprocket wheel, it is kept in mesh by another guide roller, which maintains an easy pressure upon the film to keep it in contact with the wheel, this grip being ensured under the tension of a spring. The roller is mounted on the end of a small lever, which can be moved slightly so as to release the grip upon the sprocket wheel in order to insert the film. The arrangement adopted enables the contact roller to ride over any variations in the thickness of the films should such exist—a remote possibility in view of the wonderful mathematical accuracy with which the films are made to-day. It is impossible for the film to jump the sprocket wheel, even when the machine is run at a very high speed. The contact roller is so mounted, however, that it offers no resistance to the free passage of the film.

The film now passes behind the lens for exposure, travelling through what is known as the “gate,” which consists of two parts, one fixed and rigid, the other having a slight swinging movement. By means of the gate the film is guided evenly into position, and held rigidly behind the lens during exposure. The swinging part of the gate is clamped to the fixed section by means of a spring catch, so that when the gate is closed the film is imprisoned between two sheaths which hold it firmly, and keep the surface flat and even during exposure. The end of the focussing tube C presses against the moving part of the gate and tends to hold it rigid.

The film is pulled through the gate by an ingenious plan. There are two claws or hooks F, the points of which engage with a perforation on either side of the film. These two fingers are controlled by an up-and-down cam movement attached to the bottom sprocket. As the latter revolves, the hooks are lifted and carried upward. Reaching the limit of their upward travel, they drop upon the film, clutching it by the perforations, and as the claw action has a sharp downward movement, the gripped film is pulled down suddenly and smartly through the gate three-quarters of an inch at a time. The extent of the downward travel reached, the claws are lifted so as to disengage with the film, are swung upwards once more, and the same cycle of operations is repeated until the whole length of film has been exposed.

After the exposure is made, the film passes downwards and through mechanism which is almost a duplicate of that immediately above the lens. It passes under the rocking contact roller, which keeps the perforations meshed with the teeth on the sprocket wheel, after passing round which it continues under a guide roller, and enters the lower film box B, where it is wound on a bobbin.

Action is imparted by the rotary movement produced by the turning of the handle through suitable mechanism, which is carried in a small space on the opposite side of the camera to that containing the film. The handle, however, not only supplies the drive to the intermittent film moving action, but also rotates the shutter steadily and continuously, through gearing. The shutter is mounted in a small special compartment behind the lens and in front of the film. It is adjustable; that is, the opaque sector can be increased or reduced in area so as to increase or diminish the size of the opening; thus the period of exposure can be varied according to the light, and as a supplement to the stopping down of the lens. The gearing is practically the same in all English cinematograph cameras, namely, 8 to 1, and the turning speed should be two revolutions per second, which is practically the slowest speed permissible.

The preparation of the camera for exposure is as follows. The operator has selected his working position, and the camera has been set up rigidly and firmly on its tripod, so that no oscillation can occur during exposure. The side of the camera is opened, and the loaded film box, from the slit in the bottom of which the end of the film protrudes, is slipped into the upper compartment.

Next the subject is focussed. The eye-piece of the focussing tube is made telescopic, as a rule, so that it can be extended a slight distance from the back face of the camera case to facilitate focussing; it is fitted invariably with a light-tight screw cap or gravity fall shutter, which closes over the eye-piece so that no light may enter through the tube to fog the film. For focussing purposes a piece of transparent film with a rough “Matt” surface is used. This is inserted in the film gate to act in the same way as the ground glass screen in the ordinary stand camera. The object is focussed by turning the screw, which racks the lens forward or backward as desired. When the picture appears sharp and clearly defined the matt film is removed, the cap is replaced on the eye-piece, and the latter is pushed home flush with the surface of the wood casing.

The film is now threaded. It will be observed that a slight loop is made at either end of the gate. This is necessary in order to give sufficient play to the film to enable the latter to be jerked down without any strain with each movement of the hook-claws behind the lens. If it were pulled directly off the top sprocket the film would be torn. The loops are kept constant, the upper being connected to the lower sprocket through mechanism so that they revolve simultaneously. Consequently three-quarters of an inch of film is fed into the top loop gate at the same time as three-quarters of an inch of film is jerked through the lower side of the gate.

In loading, care must be taken that the sensitised surface is brought towards the lens, and that the object is not taken through the thickness of the celluloid base. In order to thread the film through the gate the focussing tube is pushed back slightly—it is made telescopic for the purpose—the spring catch of the gate is released, and the moving part swung back. The film is now slipped into the gate, care being taken to see that the hooks of the device whereby it is intermittently pulled down after each exposure engage with the perforations. The gate is now closed, and the focussing tube under the action of a spring returns to its original position. Finally the film is led into the unexposed film box, where it is secured by a clip to the spindle of the reel. The box is shut, the handle is given a turn to make sure that the mechanism runs evenly and smoothly, and then the camera is closed, all being ready for taking the pictures.

There is a popular impression that the operation of the cinematograph camera is as simple as turning a coffee-mill or a barrel-organ, and that the cinematographer has nothing else to do but to revolve the crank. Never was there a greater fallacy.

Turning the handle appears remarkably easy at first sight, but a short trial proves that appearances are deceptive. It is essential that the handle should be rotated at uniform speed, and occasionally it is no easy matter to resist the desire to slow down. For instance, when a funeral is passing, there is an almost irresistible inclination to slacken speed. The amateur responds to this desire, and is astonished at the dislocated character of his pictures when projected upon the screen. As a matter of fact, the slowest funeral procession has to be taken with the same number of revolutions per second, and the same number of exposures—sixteen pictures per second—as an express train travelling at 60 miles an hour; the crawl of the tortoise has to be photographed just as rapidly as a horse race, in order to secure natural motion. If a subject has been photographed too slowly it cannot be corrected by accelerating the speed in projection. The judgment of the actinic value of the sunlight, and the requisite stop for the lens, as well as the adjustment of the shutter, are factors which only can be determined from experience.

Possibly the box A contains a roll of film measuring 300 feet, whereas the subject photographed only demands the exposure of 60 or 100 feet. Then one makes a few punch marks on the film by the manipulation of a small brass knob projecting from the outside of the camera, and marked “film punch.” When the film reaches the developing room, the operators working in the ruby light can tell by these marks the ends of a series of exposures.

When the upper box has been exhausted of film, the lower box, now charged with exposed film, is removed, the empty upper box is slipped out of its compartment and re-inserted into the lower recess, to serve in turn as a receptacle for film after exposure, and a fresh loaded film-box is placed in the upper space, the mechanism being threaded as before. The operator can ascertain at a glance how much film still remains to be used, because on the outside of the case is a dial which registers in feet the amount of film exposed, and which is set to zero whenever a fresh box of film is inserted.

The task of the operator is increased in difficulty where the subject being taken is moving at great speed horizontally and vertically at the same time, when the object passes in a very short while beyond the field of the lens, and in order to secure a good record the operator must follow the movements steadily and smoothly in such a way as to keep the object near the centre of the picture. The development of aviation has taxed the capabilities of the cinematographer to a supreme degree; for in photographing moving objects in the air the camera has to be trained in two directions at the same time.

For this work a special tripod is required. It has a flat table, but by means of two gear wheels the camera can be swung round panoramically, that is, in a horizontal direction, while another wheel will move it up or down through as large a vertical arc as required. Rigidity and freedom from oscillation are essential to secure sharp, well-defined pictures, and consequently this moving table has to be of massive construction, while the worm and wheel gearing has to be heavy to ensure steady movement. The camera is fitted with a direct view finder, whereby the operator can train his instrument so as to keep the subject well in the picture. Both horizontal and vertical training movements are carried out by means of hand-wheels.

One of the finest examples of the operator’s skill that I have ever seen was a film of Wilbur Wright’s flying exploits in France, on the occasion of his first visit to Europe. The camera was manipulated by two men. One concentrated his energies on the revolution of the photographing handle, while the other, with his eyes glued to a special direct view-finder devised for this particular operation, kept the camera steadily and regularly trained both horizontally and vertically upon the aviator as he described his evolutions in the air. Their joint efforts were so successful that they produced a film free from that dislocated or jerky action which as a rule characterises the lateral or vertical movement of the camera while exposures are being made; the results were just as if the camera had been kept stationary during the whole time.

The ordinary tripod is used generally for outdoor work. Many American and Continental film producers, however, resort to a special type of support for the camera in the studio or for indoor operations, such as the filming of plays. This is a solid metal pillar, recalling a machine-gun mounting, fitted with wheels to facilitate movement from point to point, and other adjusting devices. It is an excellent support for indoor work, as it ensures a solid foundation for the camera, free from vibration. In many instances the camera is driven by an electric motor.

It is sometimes desirable to secure two negative records of an important event or subject, so that, should one film prove defective, the mechanism break down, or the film be damaged or destroyed, the duplicate is available and prevents a total loss. For this purpose the camera is in duplicate, though contained within a single case, with two lenses mounted side by side as in a stereoscopic camera. Both sets of mechanism are operated by the single handle, and one person suffices for the operation of the instrument.

Within a few years, cinematography has widened its sphere of usefulness in a novel and unexpected way. Forty years ago no expedition of importance set out without some member who possessed artistic ability, that pictorial records of the life and character of the new country might be brought back to civilisation. As photography developed, the artist of palette and brush was superseded by a man armed with a camera. To-day the latter gives way in his turn to the cinematographer, who brings back to us marvellous animated pictures of the remote and unknown corners of the globe.

An ingenious camera has been devised for this especial field of enterprise. It contains a unique feature that had not been previously applied to the art. Two investigators, Newman and Sinclair, by dint of considerable experiment and labour, have succeeded in producing a moving-picture camera with a reflex attachment, and this without increasing the size of the case, or interfering with the action of the short-focus lenses. By means of this apparatus focussing can be accomplished in fifteen seconds, without disturbing the film in the gate, which is threaded up, ready for use, before the camera is taken from the dark room. In this way the camera can be operated in much less time than is possible by means of the ordinary cinematographic apparatus.

As may be seen from the diagram, Fig. 6, the internal mechanism of this handy little camera differs radically from the description given in the first part of the present chapter. The two film boxes are placed side by side instead of one above the other. The film goes into and out of them through narrow mouths, which, when the camera is closed and light-tight, are automatically increased in size to facilitate the passage of the film, and automatically decreased again when the camera is re-opened. In order to see, arrange, and focus the picture, it is only necessary to raise a knob on the top of the camera, which renders the image visible by means of a magnifying eye-piece without disturbing the film. The shutter is also adjusted from the outside of the camera, and can be closed to give an exposure of 1/100th of a second.

This camera is one of the most compact, portable, and lightest cinematograph instruments yet evolved for the purposes of hard work. It is designed to carry either 400 or 500 feet of film, and, when a picture is finished, the end of the subject on the film is indicated by a device which cuts a tongue-shaped opening in the film, and which can be readily detected by touch when the film is uncoiled in the dark room. It is an ideal instrument for travellers, explorers, scientists, and others to whom quick work is imperative. Its many excellent qualities received recognition from Captain R. Scott, R.N., who included it in the scientific equipment for the latest British Antarctic expedition.

For special work, the usual form of camera is altered in certain details, or equipped with special devices. Such modification is emphasised particularly for the purpose of taking trick pictures, to which subject reference is made in subsequent chapters.