A display apparatus including pose-tracking means; image renderer per eye; liquid-crystal device including liquid-crystal structure and control circuit; and processor. Processor is configured to: process pose-tracking data to determine user's head pose; detect if rate at which head pose is changing is below predefined threshold rate; if yes, switch on lock mode, select head pose for session of lock mode, and generate output image frames according to head pose during session; if no, generate output image frames according to corresponding head poses of user using pose-tracking data; and display output image frames, whilst shifting light emanating to from pixels of image renderer to multiple positions (P1-P9) in sequential and repeated manner, said shifting causes resolution of output image frames to appear higher than display resolution of image renderer.