CH453883A

CH453883A - Cinematographic camera

Info

Publication number: CH453883A
Application number: CH318967A
Authority: CH
Inventors: Thevenaz Jean
Original assignee: Paillard Sa
Priority date: 1967-03-03
Filing date: 1967-03-03
Publication date: 1968-03-31
Also published as: AT271202B

Description

Camera cinematographique Dans la technique cinematographique de prise de vues, il arrive souvent qu'un usager desire executer 1e passage dune scene ä la suivante par un fondu enchaine. Cette operation demande de terminer la premiere scene par un fondu de fermeture, c'est-ä-dire en diminuant progressivement 1'exposition du film jusqu'ä ce qu'on obtienne pratiquement 1'obscurite complete. Ensuite, 1e film est deplace en marche arriere sur une longueur egale ä Gelle pendant laquelle 1e taux d'exposition a ete diminue progressivement, ce retour en arriere se faisant, bien entendu, saus exposition du film. La scene suivante est prise alors en effectuant un fondu d'ouverture, c'est- ä-dire en debutant la scene avee une tres forte sous- exposition et en reglant progressivement 1e degre d'expo- sition pour que celle-ci soit correete lorsqu'une longueur de film egale ä Gelle du film passe en marche arriere a defile devant 1'objectif. Cinematographic camera In the cinematographic technique of taking pictures, it often happens that a user wishes to execute the transition from one scene to the next by a cross-fade. This operation requires ending the first scene with a fade out, that is to say, by gradually decreasing the exposure of the film until you obtain practically complete darkness. Then, the film is moved in reverse over a length equal to Gelle during which the exposure rate has been gradually reduced, this reversal taking place, of course, without exposure of the film. The next scene is then taken by performing a fade in, that is to say by starting the scene with a very strong underexposure and by gradually adjusting the degree of exposure so that it is correct. when a length of film equal to Gelle of the film passes in reverse has passed in front of the lens.

En pratique, il est tres difficile de realiser des fondus enchaines irreprochables, Gar dans les appareils cou- rants pour amateurs, il est tres difficile d'apprecier avec precision la longueur de film qui a defile devant 1'objee- tif pendant 1e fondu de fermeture et de faire retourner 1e film en arriere de rette meine longueur. In practice, it is very difficult to achieve flawless cross-fadings. With current amateur cameras, it is very difficult to assess with precision the length of film that has passed in front of the lens during the fade-out. closing and to make return the 1st film in back of rette same length.

La presente invention a pour but de faciliter dans une grande mesure 1'execution correcte de fondus enchaines. The object of the present invention is to greatly facilitate the correct execution of cross fades.

L'invention a pour objet une camera cin6matogra- phique comprenant des moyens pour faire varier 1e degre d'exposition du film au cours de la prise de vues, afin de realiser des fondus de fermeture et d'ouverture, rette camera etant munie d'un mecanisme d'entrainement du film permettant de faire revenir 1e film en marche arriere, rette camdra etant caracterisee en ce qu'elle presente un dispositif avertisseur sonore cooperant avec un organe tournant du mecanisme d'entrainement pour fournir des impulsions sonores dont 1e nombre est lineairement proportionnel ä la longueur de film entraine, ce dispositif avertisseur etant relie ä un organe de com- mande des moyens de variation de 1'exposition, de fagon ä emettre des signaux sonores lorsque Ges moyens sont mis en aetion. The subject of the invention is a cinematographic camera comprising means for varying the degree of exposure of the film during the shooting, in order to produce fade-outs and fade-ins, this camera being provided with a film drive mechanism making it possible to return the film in reverse, this camera being characterized in that it has a sound warning device cooperating with a rotating member of the drive mechanism to supply sound pulses, the number of which is linearly proportional to the length of film driven, this warning device being connected to a control member of the exposure variation means, so as to emit sound signals when the means are activated.

Le dessin annexe represente, schematiquement et ä titre d'exemple, une forme d'execution du mecanisme dquipant une camera objet de 1'invention. The appended drawing represents, schematically and by way of example, one form of execution of the mechanism equipping a camera which is the subject of the invention.

La fig. 1 est une vue laterale dune partie du meca- nisme de rette camera. fig. 1 is a side view of part of the camera mechanism.

La fig. 2 est une coupe selon la ligne II-lI de la fig. 1. La fig. 3 est une coupe selon la ligne 111-11I de laRTI ID="0001.0270" WI="5" HE="4" LX="1179" LY="1731"> fig. 1. fig. 2 is a section along line II-II of FIG. 1. Fig. 3 is a section along line 111-11I of the RTI ID="0001.0270" WI="5" HE="4" LX="1179" LY="1731"> fig. 1.

La fig. 4 est une coupe selon la ligne IV-IV de la fig. 1. fig. 4 is a section along line IV-IV of FIG. 1.

La camera peut etre tout ä fait classique pour la plus grande partie de son dispositif, de Sorte que seules les parties se distinguant du mecanisme des camdras ordi- naires ont ete representees au dessin. The camera can be quite conventional for the greater part of its device, so that only the parts distinguishable from the mechanism of ordinary cameras have been represented in the drawing.

Toutes les cameras classiques comprennent un mecanisme pour faire defiler par saccades 1e film devant un objectif, ce mecanisme d'entrainement du fihn etant accoupld ä un obturateur interceptant les rayons lumi- neux pendant que 1e film se deplace devant 1'objectif et laissant passer Ges rayons pendant que 1e film est arrete entre deux mouvements d'avance successifs. All conventional cameras include a mechanism for jerking the film past a lens, this film drive mechanism being coupled to a shutter which intercepts the light rays as the film moves past the lens and allows the film to pass. rays while the film is stopped between two successive advance movements.

Le film ä exposer peut eire place Sur une bobine debitrice, tandis que 1e film expose est enroule Sur une bobine receptrice. Dans certains Gas, la camera est des- tinee ä recevoir un magasin contenant 1e film ä exposer et destine ä recevoir egalement 1e film expose, ce maga- sin comprenant alors des moyens d'enroulement du film expose. The film to be exposed can be placed on a take-up reel, while the exposed film is wound on a take-up reel. In some Gases, the camera is intended to receive a magazine containing the film to be exposed and is also intended to receive the exposed film, this magazine then comprising means for rolling up the exposed film.

Dans tous les Gas, la camera doit comprendre un dispositif d'entrainement des moyens d'enroulement du film. Ce dispositif est represente aux fig. 1 et 3 et com- prend un pignon dente 1 monte Sur un arbre moteur 2. Ce pignon 1 engrene avec une roue dentee 3 qui est accouplee ä une roue dentee 4 gräte ä une garniture de friction 5. Les rohes dentees 3 et 4 sont pressees l'une contre 1'autre par un ressort, nun represent6, de fa@on que la garniture 5 soit serree entre res deux roues. La roue dentee 4 transmet son mouvement ä une roue den- t & 6 qui est fixee Sur un arbre 7 assurant 1'entrainement des moyens d'entrainement du film. Les roues dentees 3 et 4 et la garniture de friction 5 constituent un accou- plement ä glissement qui permet ä Farbre 7 d'exercer um couple constant et de prendre une vitesse correspon- dant ä chaque instant ä la vitesse angulaire des moyens d'entrainement. Comme an 1e sait, rette derniere vitesse varie en fonetion inverse du diametre de la torche de film enrottle. In all Gas, the camera must include a device for driving the film winding means. This device is shown in Figs. 1 and 3 and comprises a toothed pinion 1 mounted on a motor shaft 2. This pinion 1 meshes with a toothed wheel 3 which is coupled to a toothed wheel 4 grating on a friction lining 5. The toothed wheels 3 and 4 are pressed one against 1'autre by a spring, nun represented, so that the lining 5 is clamped between res two wheels. The toothed wheel 4 transmits its movement to a toothed wheel 6 which is fixed on a shaft 7 ensuring the drive of the film drive means. The toothed wheels 3 and 4 and the friction lining 5 constitute a slip coupling which allows the shaft 7 to exert a constant torque and to take on a speed corresponding at all times to the angular speed of the drive means. . As we know, this last speed varies inversely with the diameter of the wrapped film torch.

La catnera est en outre munie de moyens permettant de faire varier progressivement 1'exposition du film, res moyens pouvant etre constitues par 1e diaphragme, par um obturateur ä angle d'ouverture variable, ou encore par un filtre neutre progressif se depla@ant Sur 1e trajet des rayons lutnineux, de fa@on ä en absorber une plus ou möins grande partie. Les moyens de variation de 1'exposition du film. quel que soit 1e type choisi, sont actionnes par une tige coulissante 8, representee ä la partie inferieure de la fig. 1. Cette tige 8 est deplacee par 1e bec 9 d'un levier 10 fixe Sur un arbre 11. Cet arbre 11 pe ut etre entraine en rotation au moyen d'un bras de commande 12. The catnera is further provided with means making it possible to gradually vary the exposure of the film, res means being able to be constituted by the diaphragm, by a shutter with variable opening angle, or even by a progressive neutral filter moving on the path of the light rays, so as to absorb a greater or lesser part of them. The means of varying the exposure of the film. whatever the first type chosen, are actuated by a sliding rod 8, shown in the lower part of FIG. 1. This rod 8 is moved by the first beak 9 of a lever 10 fixed on a shaft 11. This shaft 11 can be driven in rotation by means of a control arm 12.

Le levier 10 est accouple par une bielfette 13 ä un levier 14 pivote Sur un teton 15. Ce levier 14 presente un bras 16 dont 1'extremite peut eire placee Sur 1e che- min dune saillie 17 de la roue dentde 4. Cette saillie est formee par une languette recourbee, decoupee dans 1e voile de la roue dentee 4. Le levier 14 presente un decro- chement entre son articulation Sur 1e teton 15 et son point de liaison ä la bielfette 13, ce decrochement formant une paroi transversale 18. The lever 10 is coupled by a rod 13 to a lever 14 pivoted on a pin 15. This lever 14 has an arm 16, the end of which can be placed on the path of a projection 17 of the toothed wheel 4. This projection is formed by a curved tongue, cut in the veil of the toothed wheel 4. The lever 14 has a recess between its articulation on the pin 15 and its point of connection to the rod 13, this recess forming a transverse wall 18.

La partie inferieure de rette paroi transversale 18 constitue un bec 19 cooperant avec une lame vibrante 20 fixee ä une paroi 21 (fig. 3) de la camera par un teton 22. L'extremite libre 24 de rette lame vibrante 20 est destinee ä cooperer avec des pans inclines 25 et 26 cons- tituant des saillies dune rondelle 27 fixee Sur Farbre 2. Dans la position representee au dessin, 1e bec 19 main- tient la lame 20 hors des trajets des saillies 25 et 26. The lower part of this transverse wall 18 constitutes a beak 19 cooperating with a vibrating blade 20 fixed to a wall 21 (FIG. 3) of the camera by a stud 22. The free end 24 of this vibrating blade 20 is intended to cooperate with inclined faces 25 and 26 constituting projections of a washer 27 fixed on the shaft 2. In the position shown in the drawing, the nose 19 keeps the blade 20 out of the paths of the projections 25 and 26.

Lorsqu'un fondu de fermeture doit eire realis6, 1'arbre 11 est entraine en rotation en sens inverse des aiguilles dune muntre par une action Sur 1e bras 12, ce qui deplace la tige 8RTI ID="0002.0277" WI="6" HE="4" LX="483" LY="2005"> vers 1e bas en provoquant une expo- sition d6croissante du film. En meme temps, 1e levier 14 pivote dans 1e sens inverse des aiguilles dune muntre, de Sorte que son bec 16 vient se placer Sur 1e chemin de la saillie 17 pour bloquer la roue dentee 4, tandis que son bec 19 libere la lame vibrante 20. Pendant la dur6e du fondu de fermeture, la roue dentee 4 est bloqude, de Sorte que Je film West plus enroule dans 1e dispositif recepteur. Toutefois, les roues dentees 1 et 3 continuent ä tourner, 1e glissetnent etant total entre la roue 3 qui tourne et la roue 4 qui est bloquee. La rondelle 20 tourne en meme temps que 1e pignon dent6 1, et chacune de ses deux saillies 25, 26 vient ä tour de röle cooperer avec l'extremite de la lame vibrante 20 pour 1'ecarter de sa position de repos et la relächer brusquement. La lame vibrante timet une succession de signaux sonores au rythme du passage des saillies 25, 26 Sur son extre- mite. La frequente de res signaux sonores est, de prefe- rence. de fordre de deux par seconde. Ainsi. des que Pusager agit Sur 1e bras 12 pour effec- tuer un fondu de fermeture, il entend une succession de tops sonores, et il lui suffit de compter 1e nombre de ceux-ci jusqu'ä la fin de son fondu de fermeture pour savoir quelle est la longueur de film utilisee pour effec- tuer ce fondu. Lorsqu'il effectue 1e retour en arriere du film, 1e pignon dente 1 tourne en sens inverse, de Sorte que les saillies 25 et 26 cooperent de nouveau avec_ la lame vibrante 20. 11 suffit donc ä Fusager de compter de nouveau les signaux sonores se produisant pendant 1e retour du film en arriere et d'arreter 1e mouvement de retour du film lorsqu'il a compte 1e meme nombre de signaux que pendant 1e fondu de fermeture. L'usager est alors assure d'avoir fait revenir en arriere la meme lon- gueur de film que celle qui a dUile devant Fobjectif pen- dant 1'execution du fondu de fermeture. When a fade out is to be performed, the shaft 11 is rotated counter-clockwise by an action on the first arm 12, which moves the rod 8RTI ID="0002.0277" WI="6" HE ="4" LX="483" LY="2005"> downwards causing a decreasing exposure of the film. At the same time, the first lever 14 pivots in the first counter-clockwise direction, so that its beak 16 is placed on the first path of the projection 17 to block the toothed wheel 4, while its beak 19 releases the vibrating blade 20 For the duration of the fade out, gear 4 is locked, so that the film is no longer wound up in the receiver device. However, the toothed wheels 1 and 3 continue to turn, the slippage being total between the wheel 3 which turns and the wheel 4 which is blocked. The washer 20 rotates at the same time as the toothed pinion 1, and each of its two projections 25, 26 comes in turn to cooperate with the end of the vibrating blade 20 to move it away from its rest position and release it suddenly. . The vibrating blade gives a succession of sound signals to the rhythm of the passage of the projections 25, 26 On its end. The frequency of sound signals is preferably. to ford two per second. So. As soon as the user acts on the arm 12 to effect a fade-out, he hears a succession of audible beeps, and he only has to count the number of these until the end of his fade-out to know which is the length of film used to effect this fade. When he reverses the film, the toothed pinion 1 rotates in the opposite direction, so that the projections 25 and 26 again cooperate with the vibrating blade 20. It is therefore sufficient for the user to count the sound signals again. producing during the rewind of the film and to stop the rewind movement of the film when it has counted the same number of signals as during the fade out. The user is then assured of having rolled back the same length of film as that which fell in front of the lens during the execution of the fade-out.

11 est bien entendu que des modifications peuvent eire apportees au dispositif decrit. En particulier, lors- que la camera est pourvue dune bobine receptrice du film impressionne, il n'y a pas de difficult6 ä devider rette bobine Tors de la marche arriere, de Sorte qu'il est inutile de prevoir un blocage du mecanisme d'entraine- ment du film expose pendant 1'execution du fondu de fermeture. Toutefois, 1e blocage de la roue dentee 4 est important dans 1e ras oü la camera est destinee ä rece- voir un magasin du genre Jans lequel 1e film impres- sionne ne peut plus eire retire hors du magasin RTI ID="0002.0552" WI="13" HE="4" LX="1840" LY="1207"> lorsqu'il a ete enroule Jans celui-ci. It is understood that modifications can be made to the device described. In particular, when the camera is provided with a take-up reel of film, there is no difficulty in unwinding this reel when reversed, so that it is unnecessary to provide for a blocking of the mechanism of dragging of the exposed film during the execution of the fade-out. However, the blocking of the toothed wheel 4 is important in the case where the camera is intended to receive a magazine of the Jans type in which the printed film can no longer be removed from the magazine RTI ID="0002.0552" WI= "13" HE="4" LX="1840" LY="1207"> when rolled up in this one.

Bien entendu, 1e nombre des saillies 25 et 26 peut etre choisi en fonction de la vitesse du pignon 1 et de la frequente des signaux desiree. - Of course, the first number of the projections 25 and 26 can be chosen according to the speed of the pinion 1 and the frequency of the signals desired. -

Claims

Cinematographic camera comprising means for varying the degree of exposure of the film during the shooting, in order to produce fade-outs and fade-ins, this camera being provided with a mechanism for driving the film for reversing the film in reverse, characterized in that it has an audible warning device cooperating with a rotating member of the drive mechanism to provide sound pulses the number of which is linearly proportional to the length of the film driven, this warning device being connected to a control member of the exposure variation means, so as to emit sound signals when the means are put into action. SUB-CLAIMS 1. Camera according to claim, characterized in that the first warning device comprises a vibrating blade cooperating with at least one projection provided on a rotating mobile of the film drive mechanism.

2. Camera according to claim and sub-claim 1, characterized in that the exposure variation control member is received by a pusher acting on the vibrating plate to move it away from the path of the projection when said exposure variation means are not in action.

3. A camera according to claim and sub-claims 1 and 2, characterized in that the number of protrusions is chosen so as to produce sound pulses at a frequency of about two per second when the drive mechanism film is driven at normal speed.

4. A camera according to claim and sub-claim 1, wherein the film drive mechanism comprises a slip clutch for causing winding of the film exposed in a magazine, characterized in that it comprises a control member of the warning device arranged in such a way as to block a rotatable mobile end through the sliding coupling as soon as the warning device is put into operation.

5. Camera according to claim and sub-claims 1 to 4, characterized in that the control member of the exposure variation means is coupled to a lever acting, in a bet, on the vibrating plate. to move it aside and respectively to allow it to be placed on the path of said projection and, on the other hand, on a projection of the rotating mobile driven by the sliding coupling to block the latter in rotation.