The American Amateur Photographer Volume 15

The American Amateur Photographer Volume 15

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 edition. Excerpt: ...allow; refocusing becomes necessary, probably also stopping down to get reasonable sharpness. This focusing practically puts the swingback out of the question for all scale-set hand cameras, even if the stopping down did not make exposure too long for hand support. From these considerations distortion caused by the inclined plate must always be a difficulty to the hand-camera worker with subjects containing vertical lines, unless some other method of coping with the evil is available. This is fortunately the case, though the panacea about to be described does not seem to be much used. It is well-known that if the distorted image is projected on a suitably inclined screen the rays of light from the portions of the image that are too close together will have farther to travel, and so diverge wider than those parts that are too wide apart, thus making the distorted vertical lines once more parallel. The same result is, of course, obtained by inclining the negative instead of the screen. The difficulty, however, of getting focus all over with this method of correction is the same as with the swingback in the taking camera, but a small stop may be used, as any required time of exposure can be given. Even this trouble can be avoided, greater distortions corrected, and sharper focus obtained by inclining the screen aswell as the negative, but in opposite directions. The inclination in either case need only be the half of what was formerly required, and the image will be sharp all over, even with large aperture, as may be seen from the following consideration.' Imagine the distorted image placed with its converging lines downwards, and let the top of the negative be inclined away from the lens. Incline the top of the screen also away from the...show more

Product details

  • Paperback | 278 pages
  • 189 x 246 x 15mm | 499g
  • Rarebooksclub.com
  • United States
  • English
  • black & white illustrations
  • 1236752872
  • 9781236752871