SIGMA DP3 Quattro - Manual (Page 45)

45
A APERTURE PRIORITY AE
After you set the aperture, the camera will determine the appropriate
shutter speed. If you select smaller apertures, depth of field will be greater.
Larger apertures tend to blur the background, as depth of field will be
shallower.
1
Set the Exposure Mode to the A position.
(The aperture value indicator is
illuminated in green.)
2
Set the desired aperture value by rotating
the Front Dial.
(The aperture value can be set in 1/3 stop
increments from F2.8 to F16.)
3
Press the shutter button “half-way” to
verify the focus and take the picture.

Depending on the selected aperture value, the camera automatically sets
the shutter speed in following range.
Aperture Shutter Speed
F2.8 ~ F3.5 30s ~ 1/1250s
F4.0 ~ F5.0 30s ~ 1/1600s
F5.6 ~ F16 30s ~ 1/2000s
WARNING !!

When is shown on the color LCD monitor, camera shake may
occur (the shutter speed is set slower than 1/80). If this mark is
displayed, please use the flash (P.87) or a tripod.

If the appropriate shutter speed is outside the range of suitable
combinations due to the subject being too bright or too dark, the shutter
speed indicator will blink. If the subject is too bright, set the aperture
value to a smaller one (larger F-number). If the subject is too dark, set
the aperture value to a larger one (smaller F-number) until the indicator
stops blinking.