The aperture cannot be adjusted in movie mode when using the LA-EA2 or LA-EA4 mount adapter with an A-mount lens.
This is normal operation. When an A-mount lens is attached and the camera is in Auto Focus (AF) mode, the aperture value is set to F3.5 or the maximum available aperture on lenses with an aperture smaller than F3.5 during movie recording. Therefore, the aperture value cannot be changed when recording with AF. To select a different aperture value, the camera must be set to Manual Focus (MF).