the main purpose of multiple exposure photography is to take two sequential images and add them on top of each other to create a single image
film cameras had to create a mechanism to avoid this being done accidentally before the film was advanced, but most had a method to allow this to be over-ridden to create arty multiple exposures
ALL Olympus OM-D cameras have an automatic multiple exposure mode
Olympus OM-D multiple exposure mode
Shooting mode as per PASM top dial, must be set to one of P, A, S, M
set shooting settings before activating multiple exposure
in the Menu, go to camera 2 and select Multiple Exposure
select options:
Frame = 2f (2 frames will be taken, but only one if Overlay = ON) to activate this mode (OFF deactivates it)
Autogain = if ON, the brightness of each frame is set to 1/2 and the images are overlaid.
Overlay = if ON, it will display all the RAW files on the camera to allow you to select a RAW image already recorded on the memory card (must have been taken by the same camera model) to be overlaid with another exposure and stored as a separate image. The number of pictures taken is one. However, the process can be repeated.
to overlay 3 or more frames:
Select RAW, and select a RAW file and use the [Overlay] option to make repeated multiple exposures.
When [Overlay] is set to [On], the images displayed when a RAW image is selected are developed with the settings at the time of shooting.
To set the shooting functions, cancel multiple exposure shooting first. Some functions cannot be set.
The camera will not go to sleep while multiple exposure is in effect.