Weston Master Exposure Meter Manual
Contents
1. 1 3oth of a second For other frames per second than 16 the shutter speed is proportional as shown in the following table 8 frames per second 1 15th I6 55 35 1 3oth 24 5 1 45th use 1 40th 32 1 6oth 48 55 1 9oth use 1 1ooth 64 55 1 120th use 1 130th Some cameras may have a different shutter speed at 16 frames per second such as 1 40th or r soth and the f stop for these should be read off against this shutter speed on the exposure dial If the shutter speed of your camera is unknown ascertain it from the camera 1nanufacturer Colour Cine Film Follow the accompanying instructions and those given for still colour film photographs Avoid extreme lighting conditions and allow the colour to provide all the necessary contrast For outdoor shots expose between ro a m and 3 p m if possible as the quality of the light is normally best during that period If the sun in shining it should be directly behind the camera Watch the reflection values of the surroundings ie a white dress can be turned pink by a red reflection Avoid shadows and subjects in shadow These are illuminated by skylight which is bluer than sunlight for which the film is balanced In an ideal scene the colour contrast is low flatly illuminated and it is taken on a clear sunny day Eleven Back Lighted Subjects If the meter is aimed directly at a back lighted subject ie one where t2. colores m s brillantes y otra de los colores m s obscuros y la flecha del cuadrante de exposiciones se debe colocar en el punto medio entre los dos valores de luz obtenidos El m todo de los l mites de brillantez centra la ex posici n en el medio del campo de la pel cula y es ideal para los trabajos medios en color Sin embargo si los colores obscuros fueran los de inter s principal p ngase la posici n A en el cuadrante del calculador enfrente del valor de luz del color m s obscuro y alternativamente Seventeen que vous voulez mettre en relief placez le rep re Gien face de la luminosit de la couleur la plus claire Cin matographie Les appareils de prise de vues de cin ma exposent une s rie d images un intervalle de temps d termin et une vitesse d obturateur constante Les ouvertures de diaphragme servent compenser les variations de l intensit lumineuse et de ce fait l exposition du film particulier avec lequel votre appareil est charg Pour obtenir les meilleurs r sultats du point de vue de l exposition il est recommand d employer la m thode de la gamme des luminosit s qui a t d crite pr demment En vous servant de cette m thode pour la cin mato graphie vous trouverez l ouverture co recte de diaphragme utiliser juste en face de la vitesse d obturateur propre votre cam ra sur le cadran du calculateur Le nombre d images par seconde est proportionnel la vitess
3. cuadrado se debe usar la escala de luz d bil Esta escala se pone en operaci n soltando el pestillo H que sujeta un disco deflector en la trasera del medidor v ase la ilustraci n de la parte superior derecha de la p gina 5 y haciendo girar el disco deflector hacia atr s contra la caja de modo que se enganche el pestillo y mantenga el disco abierto Clasificaci n de las Vistas El medidor de exposiciones mide el valor medio de la luz o brillantez que viene de la vista entera Por tanto para exposiciones normales se usa la posici n de la Fifteen cadran du calculateur qu il faut utiliser Pour les sc nes qui demandent un temps de pose inf rieur la normale c est dire les sc nes manquant de contrastes on a pr vu le rep re A Pour celles qui demandent plus d exposition que la normale c est dire pour les sc nes pr sentant des contrastes on a pr vu le rep re C M thode de la Gamme des Luminosit s Cette m thode est recommand e pour obtenir de bonnes photographies lorsqu il est indispensable que tous les objets d une sc ne soient correctement expos s Elle consiste mesurer la luminosit de l objet le plus brillant et celle de l objet le plus sombre du sujet Pour cela prenez une lecture de premier plan de l objet le plus sombre et une lecture de pe plan de l objet le plus brillant placez ensuite la fl che du cadran du calculateur au milieu de l intervalle compris entre la lumino
4. dado para la fotograf a en colores de im genes fijas NOTAS ADICIONALES Fotograf a a Contraluz Si el medidor est dirigido directamente a un objeto iluminado a contraluz la lectura del valor de la luz se inflar y dar como resultado una exposici n exag r e et il en r sultera une sous exposition Pour viter cela tournez le dos au sujet et prenez une lecture sur un objet semblable avec la lumi re derri re vous Filtres Les filtres ont un facteur de multiplication s appliquant la pellicule avec laquelle ils sont utilis s et l exposition doit tre augment e en cons quence La m thode la plus simple pour faire cette correction est de diviser le chiffre de rapidit d mulsion Weston par le facteur de correction du filtre et de r gler le cadran du calculateur du posem tre la valeur ainsi trouv e insuficiente Para vencer esta dificultad la persona que maneja el medidor debe dar la vuelta y tomar una lectura con un objeto semejante dando la espalda a la luz Filtros Los filtros tienen un factor de multiplicaci n con relaci n a la pel cula con la que se usan y la lectura del medidor de exposiciones se debe aumentar de acuerdo El m todo m s f cil de hacer este aumento es dividir la velocidad Weston de la pel cula por el factor del filtro y poner el cuadrante del calculador en el medidor con el valor resultante Nineteen SANGAMO WESTON LIMITED Head Office and Works Enfield Middlesex E
5. INSTRUCTION BOOK for the Model S141 735 WESTON MASTER II EXPOSURE METER INTRODUCTION TO METERED PHOTOGRAPHY Brightness Your exposure meter is designed to measure reflectec light or brightness and not incident light It is the reflected light which strikes the film in your camera and thus affects the exposure of the film Both the incident light ie the light falling on the subject and the reflected light or brightness vary from scene to scene You can guess at exposures and get passable results and even good results on occasions This is because some average subjects come within the margin of error from the correct exposure which modern films allow But the eye is not a light measuring device which produces infallible judgement of correct exposures Consider the brightness of your subject with the eye by all means but use your exposure meter to measure that brightness with scientific accuracy to obtain real quality in your photographs Exposure Exposure is the product of the length of time the light from the scene acts on the film multiplied by the amount of light striking it At all times this product should be approximately the same for the same film If the amount of light is small the time would be long if the amount of light is large the time would be short EXPOSURE Light x Time Controls of Exposure Since the light reflected from the scene is the light which will fall on the film camera adjustm
6. cale A Turn the exposure dial until its Arrow points to the same figures as the light reading See example at B 3 Make Camera Settings The correct settings for your camera now lie directly opposite each other the f stop lens opening settings are on row F and the shutter speeds time are on row G Any suitable combination of these figures may be selected providing they are directly opposite each other and will result in a correct exposure see Selecting the f stop on Page 6 WESTON MASTER METER 4 Unnumbered Divisions When the pointer of the light scale lies on an unnumbered division or block set the Arrow of the exposure dial in just the same way to the corresponding unnumbered division or block on the exposure dial 5 High Light Scale On the rear of the meter a hinged baffle will be found The light sensitive photo cell is directly beneath the baffle When the baffle is closed the High light scale is in use This scale measures from o to 1600 candles per square foot and is for use for all average and brightly lighted objects Keep the baffle closed if the light reading is 50 or higher 6 Low Light Scale When the light reading is less than 50 open the baffle by releasing latch H and turn it back against the case so that the latch engages holding it wide open The Low Light scale automatically appears measuring from o to 50 candles per square foot The first division 2 or 1 sth ca
7. e the higher the f stop number also that more of the objects will be in sharp focus when smaller stops are used In close ups or very near subjects bear in mind that the depth of field covered by the lens is considerably reduced and that in order to obtain sharp definition over the parts of the subject nearest and most distant from the camera the smallest possible f stop should be used CLASSIFICATION OF SCENES It will simplify the classification of scenes to remember that the exposure meter measures the average value of light or brightness coming from the entire scene Thus for normal exposures the Arrow position on the exposure dial is used For scenes requiring less than normal exposure an A position is provided for those requiring more a C position is provided Flat scenes lacking in contrast such as distant views and landscapes on dull days generally require less than normal exposure and more than normal development for best reproduction Set the A position on the exposure dial opposite the light value measured for such scenes The contrast scene such as a sunlit street with dark shadows for best reproduction requires more than normal exposure and less than normal development Set the C position on the exposure dial opposite the light value measured for these scenes Remember however that about eighty per cent of all scenes require a normal exposure and when in doubt about any scene use th
8. e Arrow position on the exposure dial Aiming the Meter Aim the meter as shown above looking across the top of the case at the subject Tilt the meter slightly downwards to avoid measuring the sky which being very much brighter than the rest of the subject will inflate the reading resulting in under exposure See that the photo cell is not obstructed by your fingers or the neck cord When making close up readings make sure that you do not cast a shadow with the meter or with your hand on the object being measured Five CAMERA POSITION METHOD The normal method of use of the meter is at the camera position i e close to the camera It is a simple method and the one used most frequently by photographers This method gives a correct exposure for the overall scene and does not isolate any particular object from an exposure point of view Make a light reading avoiding sky areas and set the exposure dial as already described Choose a combination of f stop and shutter speed consistent with the scene to be photographed A fast shutter speed is required if there is action or a small aperture high f stop number if maximum depth of field is needed Generally the Arrow position on the exposure dial should be used For flat scenes or for scenes with extreme contrast of highlights and shadows use the A or C position as described on Page 7 The camera position method should not normally be used for back l
9. e d obturateur comme il est montr sur la table se trouvant la page 11 Films Cin en Couleurs Suivez les instructions qui pr c dent et celles qui sont donn es pour les photographies en couleurs A NOTER GALEMENT Sujets a Contre Jour Si vous dirigez le posem tre directement sur un sujet clair contre jour la lecture de luminosit sera Fighteen si los colores brillantes fueran los de inter s principal entonces p ngase la posici n C enfrente del valor de la luz del color m s brillante Fotograf a Cinematogr fica Las c maras cinematogr ficas hacen la exposici n de una serie de fotograf as en un intervalo dado a una velocidad de obturador fijada El n mero focal controla las variaciones en la intensidad de la luz y por tanto la exposici n de la pel cula particular con que est cargada la c mara Para obtener los mejores resultados de la exposici n se recomienda el m todo de los l mites de brillantez que se ha descrito anteriormente Empleando este m todo para la fotograf a cinematogr fica se necesita emplear el n mero focal que est directamente enfrente de la velocidad de obturador particular de la c mara de toma en el cuadrante del calculador E n mero de fotograf as tomadas por segundo es proporcional a la velocidad del obturador como se muestra en la tabla de la p gina 11 Pel culas Cinematogr ficas en Colores S ganse las instrucciones citadas y las que se han
10. ed of repair take it to your regular photographic dealer If this is not possible pack the meter very carefully and return it with details of fault to Repair Department SANGAMO WESTON LTD Great Cambridge Road Enfield Middlesex England Thirteen INTRODUCTION A LA PHOTOGRAPHIE MESUR E Votre posem tre est congu pour mesurer la lumi re r fl chie ou luminosit avec une pr cision scientifique vous permettant d obtenir des photographies de r elle qualit L exposition est le produit du temps pendant lequel la lumi re r fl chie par le sujet agit sur le film multipli par l intensit de la lumi re qui frappe ce film Les moyens de r glage de l exposition sont l ouverture du diaphragme et la vitesse de l obturateur la premi re r gle l intensit de la lumi re et la seconde le temps pendant lequel la lumi re agit sur le film Mode d emploi du Posem tre Weston Master La l gende suivante devra tre lue en s aidant de l illustration la page 2 A Echelle de luminosit indiquant la luminosit du sujet B Chiffres sur le cadran du calculateur correspondants l chelle ci dessus Bouton de d blocage du cadran pour le r glage de la rapidit de l mulsion D Ouverture indiquant le r glage de la rapidit d mulsion E Onglet de rotation du cadran pour r glage de rapidit F Chiffres indiquant les ouvertures du diaphragme G Chiffres indiquant les vitesses d obturateur temp
11. endra grand ouvert Classification des Sujets Le posem tre mesure la valeur moyenne de la lumi re ou luminosit provenant de l ensemble de la sc ne Ainsi pour les expositions normales c est la fl che du Cuadrante del Calculador El cuadrante del calculador convierte las lecturas de la luz en las combinaciones correctas de exposici n Para obtener estas combinaciones primero se oprime el bot n C y despu s se hace girar la orejeta E hasta que aparece en la ventana D el n mero Weston de velocidad A continuaci n se coloca el medidor apun tando a la vista inclin ndolo ligeramente hacia abajo para evitar la medici n del cielo y se toma nota de la lectura en la escala de la luz A se gira el cuadrante del calculador hasta que la flecha apunta a las mismas cifras que la lectura de la luz v ase B Las puestas a punto correctas para la c mara est n ahora la una enfrente de la otra directamente los n meros focales est n en la fila F y las velocidades del obturador en la fila G Escalas para Luz Intensa y Luz D bil El medidor est provisto de una escala para luz intensa y otra escala para luz d bil v anse las ilus traciones J y K en la p gina 3 que cubren un campo de 0 a 1600 buj as por pie cuadrado La escala de luz intensa es para uso con todos los objetos iluminados con luz media y luz brillante Cuando la lectura de la luz es de menos de 50 buj as por pie
12. ents are necessary to compensate for changing scene light The controls of exposure are the f stop and shutter speed The f stop controls the amount of light and the shutter speed the length of time light acts on the film The lower the f stop number the larger the aperture On most cameras where the lens is mounted in the shutter shutter speeds written as 2 5 IO are fractions of seconds 2 being 3 etc One i A Light scale recording light value of scene B Figures on exposure dial corresponding to above C Button to release dial for film speed settings D Window indicating film speed setting E Tab to rotate dial for film speeds F Figures indicating f stops lens apertures G Figures indicating shutter speeds time Two HOW TO USE YOUR Film Speeds Your Master meter is a photo electric instrument which measures the reflected light of the subject with scientific accuracy The exposure dial converts the light readings into the correct exposure combinations Since emulsion speeds differ from one type of film or plate to another and for different kinds of illumination make sure that you use the correct number on the list of Weston Film Speed Values supplied with the Meter 1 Set for Film Speed Depress Button C then turn tab E until the Weston speed number of your film appears in window p 2 Take a Light Reading Aim the meter at the scene and note reading on light s
13. gs Seven Substituted Readings It is not always possible or convenient to take close up readings In such cases substituted readings of nearby similar objects can be made In the above example a close up reading of the hand would be a substitute for the sails of the barge and a close up reading of the river bank close by would suffice for the darkest object Similarly a white handkerchiet can often be substituted for a white wall or a lady s blouse But ensure that the lighting is the same and that the objects are similar Eight BRIGHTNESS RANGE METHOD The Brightness Range Method consists of measuring the light values of the lightest and darkest objects of the subject and thereby balancing the exposure midway between the two extremes It is the most accurate method known for the determination of correct exposure and is recommended for the best possible negative from an exposure viewpoint In an average scene various objects reflect different amounts of light the dark objects little light the bright objects rauch light In a fine photograph all objects should be correctly exposed and thus the above extremes should be measured Make a close up eading of the darkest object for example a dark hedge in the scene and note the light value Then make a close up reading of the brightest object for example a white wall again noting the light reading If you are not sure which are the dark est and lightest objec
14. he main lighting comes from behind it is obvious that the light value reading can be inflated resulting in under exposure To overcome this turn around and make the reading on a similar object with your back to the lighting For example Twelve ADDITIONAL NOTES in the above picture a close up reading could be made of your hand for the girl s face or a handkerchief for her dress This applies to all beach scenes where sand is back lighted or sparkling snow scenes Take the light reading on the snow or sand with the sun over your shoulder Direct reflections from sparkling water should be avoided when taking light readings These instructions obviously do not refer to the position of the camera Filters Filters have a multiplying factor in relation to the film with which they are used and the exposure re quired must be increased accordingly The easiest method of making this increase is to divide the filter factor into the Weston speed of the film and set the exposure dial on the meter with the resultant value For example the filter factor using a certain film may be 2 and the film speed roo Dividing roo by 2 the am 50 is used to set the film speed on the exposure ial Equipment Errors Photographic equipment is sometimes subject to small errors e g in shutter speeds and f stops Us ually these errors cancel each other but it is possible for them to be additive resulting in consistently over or under exposed fi
15. ighted snow sand or water since specular reflections can result in under exposure of the shadowed areas See Brightness Range Method But for landscapes general views and other photographs where a quick reading is wanted the camera position method is quite satisfactory THE CLOSE UP METHOD In the close up method the meter is held close to the object being photographed In this way the film is exposed particularly for the one object of interest and the background is subjugated accordingly Hold the meter close to the principal object about as far away as the object s smallest dimension The meter can be held closer than this distance but no farther away If the object is the face 6 inches is sufficient The distance can be increased to say 5 feet if it is desired to isolate a small group of people from the background or even to ro feet in the case of larger surfaces Make quite certain however that no light reaches the cell from unimportant objects When making a reading make sure that you do not cast a shadow on the subject with the meter or with your hand Also do not let your body interfere with the natural illumination of the subject To avoid casting shadows the meter may have to be held at an angle to the direct light on the subject ie you can measure the reflected brightness by standing slightly to one side Having taken a close up light reading set the exposure dial to the Arrow position and make your camera settin
16. lms These errors can be compen sated for by adjusting the listed film speeds lowering them if results are consistently under exposed and raising them if over exposed Weston Film Speeds Different developers have an influence on the effective emulsion speed value of a film A note is made of this in the Weston Film Speed List CARE OF YOUR EXPOSURE METER 1 Your Master Meter is rugged and well made but like a fine watch which it resembles in many ways it should be treated with all reasonable care 2 If the pointer of your meter does not register zero when no light strikes the cell it requires a slight adjustment Cover the cell with your hand or a card and with a small screwdriver rotate the small screw on the back of the meter below the cell until the pointer rests on zero Tilt the meter at an angle of about 45 when making the adjustment Zero adjustment however is only very occasionally necessary and should be made with great care 3 Do not leave the photo cell exposed to strong sunlight for long periods This treatment is harmful Keep the meter in its case or box when not in use 4 Do not drop the meter otherwise its jewelled bearings may suffer 5 Do not overheat the meter by leaving it on a hot radiator etc Normal tem perature or even abnormal summer temperatures will not harm the meter 6 Your Master meter is moisture proof but not waterproof so do not drop it in the lake If your meter is in ne
17. ndle per square foot is a very low order of illumination even for indoor scenes H The baffle half open and the release latch H Coston Master Y UNIVERSAL EXPOSURE METER UNIVERSAL EXPOSURE METER J High Light Scale o 1600 candles per square foot Low Light Scale o 50 candles per sauare foot Three Direct Reading Feature A useful feature of the Master Meter is that with the baffie closed and at the following Film Speed and f stop values the light reading is a direct indication of the shutter speed required e g when the pointer indicates roo the shutter speed required is r rooth sec etc Film Speed f stop 24 5 6 32 f 6 3 So f 8 100 SET 200 f 16 Four SELECTING THE F STOP For each picture you take you have the choice of a number of different exposure combinations of f stop and shutter speed As the exposure dial is set on this page you might select an f stop of f 6 3 at 1 25th sec or an f stop of f 22 at sec Any one of the combinations shown on the dial would result in a correct exposure providing the figures taken were directly opposite each other but the selection of the correct combination depends upon the requirements of the subject If the scene is an action one select a fast shutter speed and use the f stop directly opposite If maximum depth is needed then you can select a slower shutter speed with its corresponding smaller stop opening Remember that the smaller the apertur
18. ngland Scottish Factory Port Glasgow Renfrewshire Branches Glasgow Manchester Newcastle on Tyne Leeds Liverpool Wolverhampton Nottingham Bristol Southampton Brighton ADDITIONAL COPIES OF THIS INSTRUCTION BOOK ONE SHILLING EACH Twenty Printed in England D Y 9 53 10m WESTON y pu C UNIVERSAL EXPOSURE METER MODEL S141 735 SANGAMO WESTON LTD ENFIELD MIDDLESEX
19. ran du calculateur en face de la luminosit de la couleur la plus sombre Si au contraire ce sont les couleurs claires con mucho del campo de la pel cula como es natural habr que sacrificar detalles del objeto m s obscuro y o del objeto m s brillante Poniendo la posici n U de modo que est enfrente del valor de la luz del objeto m s obscuro se obtendr la exposici n correcta m nima pero si se pone la posici n O enfrente de la luz del objeto m s brillante se obtendr la exposici n correcta m xima Alternativamente se puede obtener una exposici n media empleando el medidor como ya se ha descrito Fotograf a en Colores El campo de pel culas para fotograf a en colores est cubierto por las posiciones A y C en el cuadrante del calculador Todos los objetos cuyo valor de luz caiga entre esas posiciones tendr n una exposici n correcta Los objetos que tengan un valor de luz por debajo de la posici n A estar n con poca exposici n y todos los objetos que tengan un valor de luz por encima de la posici n C estar n con una exposici n excesiva La brillantez en la fotograf a en colores se obtiene por medio del contraste entre los colores y el m todo que se recomienda para obtener la exposici n mejor es el m todo de los l mites de brillantez Se debe recordar que el negro y el blanco no se consideran como colores y no se deben medir Se debe tomar una lectura muy de cerca de los
20. re restricted than that of monochrome film The permissible range of light values is approximately 4 to 1 and this range is covered by the A and C positions on the exposure dial The A position represents the lower limit and the C position the upper limit Thus after setting the dial for any scene all objects whose light values fall between these positions will Ten COLOUR PHOTOGRAPHY be correctly exposed If any objects have a light value below the A position they will be under exposed and if any have a light value above the C position they will be over exposed This knowledge enables you to select the best exposure for the colours in which you are most interested Brilliance in colour photography is obtained through colour contrast and not from highlights and shadows as in black and white photography The method recommended for best exposures is the Brightness Range Method described on page 10 In colour work black and white should not be considered as colours and must not be measured First make a close up reading of the darkest colour in the scene Then take a close up reading of the brightest colour Set the Arrow position on_ the exposure dial midway between the light values of the darkest and brightest objects and make your camera setting The above method centres the exposure in the middle of the film range and is ideal for the average colour photograph where the colour contrast is lo
21. rrect exposure will be obtained The Arrow position gives the normal exposure When movement in a scene dictates a minimum exposure you can use the U position and although the densities on the negative will be as thin as is permissible the exposure will still be correct On the other hand in a dark hall or cave it might be impossible to obtain a reading from anything but the brightest object By using the O position the maximum range of the negative will be used and correct exposure obtained but the density will be increased Highlights and Shadows In a scene such as the above the brightness range greatly exceeds the film range i e the patches of sunlight may measure soo candles per sq ft and the deep shadows 1 candle per sq ft The average film range is thus not wide enough to give details in both the highlights and shadows although good average exposure can be obtained by using your meter as already described According to the effect you require however you can choose to expose for details in the shadows by using the U position or alter natively for detail in the highlights by using the O position Nine Colour Film Range The range of colour film is far mo
22. s de pose o Fourteen INTRODUCCI N A LA FOTOGRAF A CON EXPOSICI N MEDIDA El medidor de exposiciones se destina a medir la luz reflejada o brillantez con exactitud cient fica haciendo segura una calidad real en las fotograf as La exposici n es el producto de la duraci n del tiempo que la luz que viene de la vista act a sobre la pel cula multiplicada por la cantidad de luz que cae sobre dicha pel cula Los controles de la exposici n son la abertura de la lente y la velocidad del obturador la primera controla la cantidad de luz y la segunda la duraci n del tiempo con que la luz act a sobre la pel cula Manera de Usar el Medidor de Exposiciones Weston Master La clave siguiente debe ser le da en conjunci n con la ilustraci n de la p gina 2 A Escala de la luz que registra el valor de la luz de la vista B Cifras en el cuadrante del calculador que corres ponden a los valores del p rrafo anterior C Bot n para soltar el cuadrante para poner en su punto la velocidad de la pel cula D Ventana que indica la puesta en su punto de la velocidad de la pel cula E Orejeta para girar el cuadrante para las velocidades de las pel culas F Cifras que indican los n meros focales aberturas de la lente G Cifras que indican las velocidades del obturador tiempo Cadran du Calculateur Le cadran du calculateur transforme les lectures de luminosit en combinaisons correctes d exposition Pour ob
23. s objetos menos brillantes de la vista Esto se consigue tomando una lectura desde muy cerca del objeto m s obscuro y haciendo otra lectura de una manera semejante del objeto m s brillante A continuaci n se coloca la flecha del cuadrante del calculador en el punto medio entre los valores de la luz del objeto m s obscuro y del objeto m s brillante Entonces se pueden leer las combinaciones correctas de n mero focal y velocidad del obturador para la vista Si no fuera posible tomar una lectura muy de cerca se pueden tomar lecturas substitutas pero hay que ase gurarse de que las condiciones de iluminaci n son las mismas y de que los objetos son semejantes Las Posiciones U y O Las posiciones U O en el cuadrante del cal culador muestran los l mites de la brillantez del objeto que la pel cula media puede registrar en una sola negativa Para una preparaci n dada del cuadrante todos los objetos cuyo valor de luz caiga en esos l mites o entre ellos tendr n una exposici n correcta En una vista en la que el campo de brillanteces exceda beaucoup la sensibilit de la pellicule le d tail dans les parties les plus ombr es comme dans les parties les plus ensoleill es devra videmment tre sacrifi En placant le rep re U en face de la lecture de luminosit de l objet le plus sombre on obtiendra le temps minimum de pose correct mais si c est le rep re O que l on place en face de la lect
24. sit de l objet le plus sombre et celle de l objet le plus brillant Vous pouvez alors choisir les combinaisons correctes de diaphragme et d obturateur pour la sc ne en question S il n est pas possible de prendre une lecture de premier plan on peut faire des lectures sur des objets de m me nature mais alors il faut s essurer que les conditions de luminosit sont bien les m4mes et que les objets sont semblables Les Rep res U et O Les rep res U et 0 du cadran du calculateur donnent les limites de la gamme de luminosit que la plupart des pellicules peuvent enregistrer sur un seul n gatif Pour un r glage donn du cadran tous les objets dont la luminosit tombe sur ou entre ces limites seront correctement expos s Dans un sujet o la gamme de luminosit d passe de Sixteen flecha del cuadrante del calculador Para vistas que necesiten una exposici n menor que la normal es decir vistas que carezcan de contraste el aparato est provisto de una posici n A y para aquellas vistas que necesiten una exposici n mayor que la normal es decir vistas con contrastes el aparato lleva una posici n C M todo de los L mites de Brillantez El m todo de los l mites de brillantez se recomienda para buenas fotograf as en las que es esencial que todos los objetos de la vista tengan una exposici n correcta y consiste en medir los valores de la luz de los objetos m s brillantes y de lo
25. tenir ces combinaisons pressez d abord le bouton C ensuite tournez l onglet E jusqu ce que le chiffre de rapidit d mulsion Weston apparaisse dans la fen tre D Pr sentez alors le posem tre vers le sujet en le penchant l g rement vers le bas afin d viter de mesurer le ciel et notez la lecture sur l chelle des luminosit s A Tournez le cadran du calculateur jusqu ce que son index vienne en face des chiffres correspondant la lecture de luminosit voir B Les r glages corrects de votre appareil sont maintenant face face les ouvertures de diaphragme sur l chelle F et les temps de pose sur l chelle G Echelles des Grandes et Faibles Luminosit s Le posem tre est pourvu d une chelle grande luminosit et d une chelle faible luminosit voir illustrations J et K page 3 permettant de mesurer des luminosit s de 0 1600 bougies par pied carr On se sert de l chelle de grande luminosit pour tous les sujets de luminosit moyenne ou brillante Lorsque la lecture de luminosit est au dessous de 50 on doit se servir de l chelle de faible luminosit Celle ci est mise en op ration en d gageant le loquet H maintenant le cache charni re plac sur la face arri re du posem tre voir l illustration la partie sup rieure droite de la page 5 et en retournant le cache contre le boitier jusqu lenclenchement du loquet qui le mainti
26. ts measure several that appear so and take the lowest and highest readings respectively Set the Arrow on the exposure dial midway between the darkest and brightest object light values i e the Arrow should be the same number of divisions or blocks from the darkest light value as it is from the brightest You can then read off the correct com binations of f stop and shutter speed for the scene Most films can record a long range of brightness in any one subject but there are limits to the range of deep shadows and bright highlights which can be THE U AND O POSITIONS recorded with reasonable truth in a single negative A knowledge of these limits can prevent unnecessary loss of detail in extreme shadows or highlights when long range subjects are encountered The U and O positions on the exposure dial show the limits of subject brightness which the average film can record on a single negative the ratio of these being about 128 1 For a given setting of the dial all objects whose light values fall on or between these two limits will be correctly exposed Any object having a light value below the U position will be under exposed and any object with a light value above the O position will be over exposed By setting the U position opposite the darkest object light value the minimum correct exposure will result If the O position is set opposite the brightest object value the maximum co
27. ure de luminosit de l objet le plus brillant on obtiendra le temps maximum de pose correct On peut aussi obtenir un temps de pose moyen en se servant du posem tre comme il a t d crit pr c dem ment Photographie en Couleurs La sensibilit des pellicules en couleurs est celle indiqu e par les rep res A et C du cadran du calculateur Tous les objets dont la luminosit tombe entre ces rep res seront correctement expos s Les objets ayant une luminosit inf rieure celle de A seront sous expos s tandis que ceux dont la luminosit sera sup rieure celle de C seront sur expos s La luminosit dans la photographie en couleurs est obtenue par le contraste des couleurs et la m thode recommand e pour obtenir le meilleur temps de pose est la m thode de la gamme des luminosit s Il y a lieu de se rappeler que le blanc et le noir ne doivent pas tre consid r s comme des couleurs et qu ils ne doivent pas tre mesur s Faites une lecture de premier plan sur la couleur la plus vive et sur la couleur la plus sombre et placez la fl che du cadran d exposition au milieu de l espace compris entre ces deux lectures de luminosit La m thode de la gamme des luminosit s centre l exposition au milieu de l intervalle de sensibilit de la pellicule elle est id ale pour la plupart des photographies en couleurs Si cependant les couleurs sombres sont le principal int r t placez le rep re A du cad
28. w and flatly illuminated If however the dark colours are of principal interest set the A position on the Exposure dial opposite the darkest colour light value Alternatively if the brightest colours are of principal interest set the C position opposite the brightest colour light value These positions match the lower and upper limits of the film range respectively Usually the most pleasing colour pictures result from exposure for the brightest colours and remember that slight over exposure gives better colour rendition than under exposure Avoid shadows and extreme contrast in lighting wherever possible CINE PHOTOGRAPHY A cine camera is essentially the same as a still camera but it exposes a series of pictures in a given interval at a fixed shutter speed For the best exposure results the Brightness Range Method described on Page 10 is recommended Make close up readings of the darkest and brightest objects in the scene and set the Arrow position mid way between the light values obtained The correct f stop to use will then be found opposite the particular shutter speed of your cine camera In panning the camera watch the contrast in lighting and if possible first determine the correct exposure settings for each part of the scene altering the f stop when the camera moves from light to dark areas etc The standard number of frames exposed by the average amateur cine camera is 16 per second at a shutter speed of
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