Arax 88 v7 Instruction Manual
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Page 6 of 8
4. DETERMINING THE EXPOSURE WITH THE AID OF THE TTL/SPOT PRISM VIEWFINDER
The TTL/SPOT viewfinder provides a direct image of the subject for composition. It also provides accurate shutter
speed and aperture values with the aid of its built-in exposure meter. The TTL/SPOT viewfinder has two exposure
metering modes: averaging and spot modes. The averaging metering mode provides metering in the brightness range
from 2 to 16000 cd/m and the spot mode - from 8 to 16000 cd/m .
metering modes: averaging and spot modes. The averaging metering mode provides metering in the brightness range
from 2 to 16000 cd/m and the spot mode - from 8 to 16000 cd/m .
The averaging metering is carried out in the central area of the viewfinder field of view. The central area has an oval
shape of 30x50 mm in size. The spot metering sensitive zone is in a restricted area of rectangular shape of 5x10 mm in
size.
size.
The exposure meter is activated by pressing button 39, (SEE ILLUSTRATION) It operates for about 20 sec. and then
automatically turns off. To toggle metering modes it is necessary to press the button once again.
Integral metering Spot metering
As a power supply the exposure meter requires a battery with an initial voltage of 4-4.5 V (diameter of 11.6 mm,
length of 16.2 mm). For example, a source comprising three elements of PX675, RM675 or MS76 types. Or 3pcs 1.5V
cells, Ø 11.6mm (SR44, 357, V357, D357, SR44W).
cells, Ø 11.6mm (SR44, 357, V357, D357, SR44W).
The power supply source ensures the exposure meter operation in the temperature range from minus 5 to 45°C.
When preparing the prism viewfinder for operation set the film sensitivity on its calculator by turning handle 42 until
When preparing the prism viewfinder for operation set the film sensitivity on its calculator by turning handle 42 until
the film speed value in ISO units appears in window 43.
Set on the calculator dial the value of the lens speed by turning scale 41 until the appropriate value coincides with the
index.
The lens speed is a number corresponding to the maximum relative aperture. For example, it is 2.8 for MC ARSAT C
lens.
The exposure is determined with the camera shutter cocked.
Having pressed the exposure meter circuit actuating button, select the required operating mode (TTL or SPOT).
The illumination of the middle signal
Having pressed the exposure meter circuit actuating button, select the required operating mode (TTL or SPOT).
The illumination of the middle signal
means that spot-metering mode is ON. Illumination of the extreme
signs indicates that the averaging metering mode is on.
To change the metering mode it is necessary to press the exposure meter actuating button additional times. When the
exposure meter is on the "overexposure" indicator
or "underexposure" indicator
is lit.