Home Movies (Jan-Dec 1940)

PAGE 462 HOME MOVIES FOR OCTOBER ★ REVERSE PICTURES ★ COVERED REEL ARMS * 750 WATT LAMP ★ STILL PICTURES * AUTOMATIC LEVER RE-WIND * SILENT FINGER MOTION * COOL LAMP HOUSE WHEN RUNNING REVERSE * (.1.6 WOLLENSAK LENS * CENTRALIZED CONTROLS * SLOW SPEED FLICKERLESS PICTURES ★ PILOT LIGHT and many other features listed in our literature AMERICA'S LARGEST PROJECTOR LINE KEYSTON E KEYSTONE MFG. COMPANY • BOSTON, MASS. Meter Readings (G. Joseph, New Jersey) I should like some information before buying an exposure meter. One I am interested. in gives readings for the following lens openings: f/1.4, 2, 2.8, 4, 5.6, 8, 16, 22, and 32. My camera has an f/3.5 lens. Why doesn’t the meter give a reading for this opening ? Also, one meter I saw is calibrated in Schemer ratings and lists such speed values as 14, 17, 20, 23, 26, and 29. Why doesn’t this meter have a number 18 speed marking as ivell as other numbers I find many film distributors using in their film advertising ? The lens openings as listed on the first meter you mention are true full stops. That is, each is again as big or again as small as the opening preceding or following it. For example, f/4 is exactly one full stop larger than f/5.6. The f/3.5 opening on your camera lens would be one-half stop larger than f/4, and f/4. 5 would be a quarter ston smaller than f/4. The difference is so small that when you get a reading of f/4 you may safely use a stop of f/3.5 on one hand, or a stop of f/4. 5 if the reading leans slightly in excess of f/4. The Schemer ratings referred to are also full stons. Every three numbers in the Schemer system represents a full stop on the lens. Therefore, the difference between 17 and 18 Scheiner represents but l/3rd of a stop. If the film you use is rated at 18 Scheiner, you may safely use the 17 Scheiner reading on your meter. Fog (0. L. Rader, Maryland) I find that after reversing my film the whites lack transparency. What causes this? Lack of transparency, or fog, may be caused by several things. Too much caustic soda may be used in the processing formula; your safelight may not be 100% safe; or you may be using the wrong type bleach. It is • Readers: This department is for your benefit. Send in your problems and our technical board of professional cameramen 'will answer your question in these columns. If an answer by mail is desired, enclose addressed stamped envelope. best to use the bleach formula which calls for bichromate, as this works on the non -halation backing of most films except Eastman. Yellowish Cast (L. L. Rader, Maryland) Sometimes my home processed film has a slight yellowish cast. What is the cause of this? The yellow cast referred to may arise from two conditions: Either your developers are too weak from over-use or too weak compounding, or you fail to wash your film sufficiently long enough after each processing operation. Universal Focus (J. R. Dawns, New York City) / just purchased a Hugo Meyer // 1.5 lens for my 8 mm camera. At what point may I set it for universal focus ? When using the f/1.5 opening and setting the focus at 13 feet, tMs lens will be in universal focus from 6' 6" to infinity. At f/1.8 it will be in focus from 5'6" to infinity when set at a focus of 11 feet. An opening of f/2.5 set at 8 feet will be in focus from 4' to infinity. At f/3.5 set at 6 feet, the lens will be in focus from 2'6" to infinity; and f/4.5 focused at 4 feet will be in focus from 2' to infinity. Binocular-Telephotos (T. R. Schratt, Evanston, 111.) When using a binocular in front of my regular camera lens, the scenes are very dark. What causes this? The use of binoculars in front of your lens tends to cut down the volume of light reaching the film, depending upon the number of extra lens surfaces through ® Continued on Page 50S