Why the live view on a camera does not necessarily match the final image brightness: Taking the Sony α6700 as an example

How Live View Reflects Shooting Settings

The Sony α6700 can determine through [Live View Display] whether the effects of settings such as exposure compensation, white balance, and creative style are reflected in live view. This article only explains the preview behavior recorded in the α6700 manual and does not treat screen brightness as an accurate measurement of sensor exposure. [G-EV-01, G-EV-02]

Setting Effect On and Off

When [Setting Effect On] is enabled on the α6700, live view roughly shows the image as it would appear with the applied shooting settings; when [Setting Effect Off] is selected, images are displayed at an appropriate brightness to facilitate composition. Sony clearly notes that when the setting effect is off, live view brightness may differ from the actual recorded image. This menu and behavior are limited to the α6700. [G-EV-01, G-EV-02]

Flash Preview Has a Separate Exposure Effect Option

When [Live View Display] is set to [Setting Effect On], the α6700’s [Exposure Effect] option controls whether live view shows the flash exposure effect; Sony indicates that this option only works with Sony-made flashes. Sony also notes that when using third-party studio flashes, previews may appear darker at certain shutter speeds; when the setting effect is off, the preview is displayed brightly to facilitate composition. [G-EV-03]

Use Preview for Composition and Verify Actual Recording

The Sony manual states that when [Setting Effect] is off, live view brightness may differ from the actual recorded image. Therefore, this setting can be used for composition, but such a preview should not be interpreted as a guarantee of the final recorded brightness; important shots should be checked on the actual captured image. [G-EV-02]