Sony ILCA-77M2 - Manual (Page 56)

If proper exposure cannot be obtained after setup, the shutter speed on the shooting screen blinks.
Although you can shoot as it is, resetting is recommended.
The brightness of the image on the screen may differ from the actual image being shot.
Hint
Smaller F-value (opening the aperture) narrows the range that is in focus. This allows you to put the
subject in sharp focus and blur objects in front of and beyond the subject (depth of field becomes
shallower). Larger F-value (narrowing down the aperture) widens the range that is in focus. This
allows you to shoot the depth of the scenery (depth of field becomes deeper).
[43] How to Use Shooting Selecting a shooting mode
Manual Exposure
You can shoot with the desired exposure setting by adjusting both the shutter speed and aperture. The
shutter speed and the aperture value can be changed while recording movies.
1. Set the mode dial to M (Manual Exposure).
2. Select the desired aperture value by turning the front dial.
Select the desired shutter speed by turning the rear dial.
When [ISO] is set to other than [ISO AUTO], use MM (Metered Manual) to check the exposure
value.
Toward +: Images become brighter.
Toward - : Images become darker.
0: Appropriate exposure analyzed by the product
3. Adjust the focus and shoot the subject.
Note
When [ISO] is set to [ISO AUTO], the ISO value automatically changes to achieve the appropriate
exposure using the aperture value and shutter speed you have set. If the aperture value and shutter
speed you have set are not suitable for appropriate exposure, the ISO value indicator will blink.
The Metered Manual indicator does not appear when [ISO] is set to [ISO AUTO].
When the amount of ambient light exceeds the metering range of the Metered Manual, the Metered
Manual indicator flashes.
The (SteadyShot warning) indicator does not appear in manual exposure mode.
The brightness of the image on the monitor may differ from the actual image being shot.
Hint
You can change the shutter speed and aperture (F-value) combination without changing the set
exposure value by rotating the front/rear dial while pressing the AEL button. (Manual shift)