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Hasselblad H1D
function. By pressing the same button again therefore, the setting will revert. is means you do not have to remember which button to press as they will both produce the same desired result in this case.
Zone (system)
e Zone System is a method of combined exposure calculation/film development providing a great deal of tonal control. It was originally devised by Ansel Adams - the classic landscape photographer and Hasselblad user - and now exists in various forms for both black & white and colour photography. An integral part of the method includes the classification and grouping of any given scene into a range of nine (or ten)
Concerning the H1D, the word zone refers to the grouping and clas- sification of various tones, where Zone V is the equivalent (whether in black & white or colour) to 18%
True exposure
e effective shutter speed for a central lens shutter is defined as the length of time between the opening and closing when measured at the half height position when expressed in diagram form (see diagram ). e fact that it will take some time to open and close the shutter will have an influence on the effective shutter speed as the lens aperture
closes to its setting. e faster the shutter opens and closes, the less this influence will be. It is also follows that the influence will be greater on shorter shutter speeds.
With the lens at full aperture (largest opening), the amount of light
at the film plane appears as illustrated by the 
curve in the diagram. e effective shutter speed then becomes T1. If the lens is now closed down by one stop, the amount of light appears as il-
lustrated by the 
curve. e effective shutter speed is now increased to T2, which is longer that T1. e result is that the exposure is not reduced by exactly one stop (1EV), however, but slightly less. At the shorter shutter speeds, the exposure error can be as much as 0,5 – 0,8 EV.
e True exposure mode can compensate for this exposure error since the behaviour of the shutter is a known and predictable factor. At shut- ter speeds of 1/150 second or shorter (faster), the camera will shorten
the shutter speed to compensate, as illustrated by the 
curve. At the fastest shutter speeds, however, it is not possible to adjust the shutter speed and so the aperture is adjusted instead.
Although it is probably an infrequently used combination, please note nevertheless that the fastest shutter speed / minimum aperture combination cannot be adjusted by True exposure.
White balance
e metering and consequent adjustment for variations in colour temperature.
