International photographer (Jan-Dec 1934)

November. 1934 The INTERNATIONAL PHOTOGRAPH K R Seven varied, the other remained constant, and the variation of the one factor alone then governed the variation of speed. We should bear in mind however, that with a variation in distance of the object there is also a corresponding variation in distance between lens and plate, with a consequent variation in intensity of light, even though the aperture remains constant. This variation is of little importance when the lens is used at or near its equivalent focal distance from the plate, as for general landscape work. But when we photograph near by objects requiring the plate at a greater distance than the equivalent focus, the variation requires consideration. Using a 12 inch focus lens, take a distant landscape requiring the plate at the equiva lent focal distance, and a near object requiring a distance of 15 inches between lens and plate. With the same aperture giving the same volume of light, the intensity of light — the speed of the lens — would be vastl) different in the two instances. Being in inverse proportion to square of distance, it would be inversely as 12 x 12 and 15 \ 15, that is, as 15 x 15 and 12 x 12, or as 225 and 144, or as 25 and 16. Exposure time being in inverse proportion to intensity and speed it would be directly proportionate to square of distance between lens and plate, that is, as 12 x 12 and 15 x 15, or as 16 and 25. The near object would therefore require fully one-half again the exposure required for the landscape. (To be concluded in December ) The Photographer In Hollywood Doesn't Photograph By Bob Hussey N the "credit sheet" at the start of every motion picture is listed the name of the photographer, but he isn't the one who really photographs the production. The chap who actually operates the camera never gets his name on the screen. The photographer of a motion picture is the fellow who supervises the photography, but it's the Second Cameraman who handles the camera. He is the "Operative Photographer" of the picture, the one who manipulates the camera. One has to be a Second Cameraman before becoming the photographer and, before that, one has to be an assistant cameraman. The Second Cameraman has finished his apprenticeship and is gaining finesse and polish in his vocation before moving on to the top standing. On any movie set it is the photographer who "paints the picture." With the director he plots the action and camera movement, then proceeds to frame the scene as it will appear on the screen. It's up to the Second Cameraman to see that it gets on the screen in just that manner. Having been given instructions on what is to be photographed, the Second Cameraman makes ready to photograph the scene. (Turn to Page 25) The JL>CriS that brought the Mountain Mahomet to B Gf H Cooke faro Lens in photographing position on the Bell & Hoivell Camera. BELL & HOWELL n\L,7tr ^xew"^; Company 716 North La Brea Ave., Hollywood; 320 Regent St., London (B & H Co., Ltd.). Established 1907. /^T/^ith admirable logic, Mahomet decided to rr go to the mountain when it declined to come to him. But in motion pictures it's costly, and often impossible, to move close to the subject at will. So Bell & Howell produced the Cooke Varo Lens, which "zooms" at the cameraman's wish — and the camera doesn't leave the spot. At F 3.5 the range is from 40 mm. to 50 mm. ; at F 4.5 from 40 mm. to 85 mm., and at F 5.6 and F 8 the full "zoom," from 40 mm. to 120 mm., is obtainable. Adjustable stops limit the "zoom" as desired. One crank controls all moving parts. The iris is varied automatically with the focal length to keep the f/ value constant. Gives critical sharpness and full anastigmat correction at all points of the "zoom." Close focusing is done with auxiliary lenses. Write for full details. Sometimes available on rental to responsible studios. B &. H Cooke F 2 Speed Panchro Lenses The theater audience may register only vague dissatisfaction, wondering perhaps why an obviously good story affected them so little. But a camera man will unerringly put his ringer upon the cause, a camera lens that was inadequate. B & H F 2 Speed Panchro Lenses, corrected for the blue and red rather than blue and yellow rays, are in use wherever successful photography is turned out. Eleven focal lengths, 24 to 108 mm. B & H Cooke F 2.5 Panchro Lenses, at lower cost, meet many needs where such speed is adequate. Seven focal lengths, 35 to 162 mm. Write for prices. Please mention The International Photographer when corresponding with advertisers.