Zhumell Rangefinder RF645 - Manual (Page 16)

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3. Shooting 3-4 Exposures
The numerals 1 to 500 on the shutter speed dial represent shutter
speeds or exposure times expressed in reciprocals. In other words,
"500" actually means 1/500 second and "60" is 1/60 second.
The lens aperture can be set by rotating the lens aperture ring. The
65mm lens provides an aperture range of f/4 to f/32. Between any
two f-numbers, there is an intermediate stop with the distance/aper-
ture index line to set the aperture as required.
3-4-2 Exposure Metering System
A light metering sensor located to the side of the viewfinder objec-
tive lens measures the photographing area in five independent seg-
ments and calculates the correct exposure by a center-weighted mul-
tiple-field comparative algorithm. The metering system calculates the
correct exposure based on the lens's photographing field, the bright-
ness level of the photographic subject, the contrast among metering
segments and miscellaneous factors to achieve the best photograph-
ic image reproduction. Refer to 6. References (Exposure
Measurement Sensitivity Patterns).
Note 1: The impact on exposure settings of any filters attached to the lens must be taken
into consideration to determine the correct exposure when compensation for the exposure
determined by the external metering system of the Bronica RF 645.
Note 2: The metering range of the Bronica RF 645 is from EV 3 to EV 18 with the 65mm
standard lens at ISO 100. EV 3 (at ISO 100) is an exposure level designated by a combination
of f/4 aperture and 2 second shutter speed. EV 18 (at ISO 100) is an exposure level designat-
ed by a combination of f/22 aperture and 1/500 sec. shutter speed.
Note 3: EV level varies when any film speed other than ISO 100 is used, or exposure com-
pensation is applied. For more details refer to 6. References (Relationship Between Shutter
Speed, Aperture and Exposure).