A method that improves compensation for hard cuts and/or vertical motion effects in the conversion of 2D images to 3D images, displays 2D images to one eye and computed images to the other eye. Generating the computed images includes using an approximation variable that represents some relationship between the 2D images, such as the speed of motion across two images. Compensating for the hard cut or vertical motion effect includes temporarily setting the approximation variable to a value that makes the left and right eye images more similar (if identical, displaying a 2D image). The approximation variable can be pre-set to a value based on the speed of motion in a scene to be displayed. A method of displaying images in either 2D or 3D may include converting 3D images to 2D images by displaying images computed from images intended for either the left eye or the right eye.