Nikon 55MM F/2B Instruction Manual

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Nikon 55MM F/2B Instruction Manual Manual pdf 21 page image

When non-TTL meter is usedAt close ranges (reproduction ratios greater than1:10), the amount of light reaching the film decreasesas the lens-to-film distance increases. When non-TTLmeasurement is used for this range, the result is under-exposed photographs unless compensation has beenmade for this decrease. (When the Micro-Nikkor 55mmf/2.8 lens is used with the Photomic or NikkormatTTL meter it is not necessary to make compensations,since the meter is designed to give an accurate readingof the amount of light reaching the film.)The table on the right gives the exposure factors (com-pensation values) with exposure increase in f/stops fornon-TTL exposure measurement at reproductionratios greater than 1:10.To calculate the necessary corrections in shutterspeed rather than in aperture value, multiply a givenexposure factor by the exposure time. For instance,if the normal exposure at a 1:1 reproduction ratio is1 /8 second, the correct shutter speed is 1 /8 x 4 = 1/2second.The following formula is used to calculate the expo-sure factor: Exposure factor = (1 + R)2where R = Reproduction ratioReproductionratio1/101/81/61/41/21/1.81/1.61/1.41/1.21/1Exposurefactor1.21.31.41.62.32.42.62.93.44.0Exposureincreasein f/stopsa p p r o x . 1 / 3approx. 1/3a p p r o x . 1 / 2a p p r o x . 2 / 3approx. 1-1/3approx. 1-1/3a p p r o x . 1 - 1 / 3a p p r o x . 1 - 1 / 2approx. 1-2/3a p p r o x . 221