Sony ILCE-7S - Manual (Page 61)

You can express the movement of a moving subject in various ways by adjusting the shutter
speed, for example, at the instant of the movement with high speed shutter, or as a trailing
image with low speed shutter. The shutter speed can be changed while recording movies.
1. Set the mode dial to S (Shutter Priority).
2. Select the desired value by turning the front dial.
3. Adjust the focus and shoot the subject.
The aperture is automatically adjusted to obtain proper exposure.
Note
If proper exposure cannot be obtained after setup, the aperture value on the shooting
screen blinks. Although you can shoot as it is, resetting is recommended.
Use a tripod to prevent blurring when you use a slow shutter speed.
The (SteadyShot warning) indicator does not appear in shutter speed priority
mode.
When the shutter speed is 1 second(s) or longer, noise reduction will be done after
shooting for the same amount of time that the shutter was open. However, you cannot
shoot any more while noise reduction is in progress.
The brightness of the image on the monitor may differ from the actual image being shot.
Hint
When a faster shutter speed is used, moving subjects, such as a running person, cars, or
sea spray come out as if they are frozen in their movements. When a slower shutter
speed is used, a trailing image of the movement of the subject is captured to create a
more natural and dynamic image.
[40] How to Use Shooting Selecting a shooting mode
Aperture Priority
You can shoot by adjusting the aperture and changing the range in focus, or by defocusing
the background. The aperture value can be changed while recording movies.
1. Set the mode dial to A (Aperture Priority).
2. Select the desired value by turning the front dial.
Smaller F-value: The subject is in focus, but objects in front of and beyond the
subject are blurred.
Larger F-value: The subject and its foreground and background are all in focus.