Depth increases wonderfully the more one views images 1 to 4 (I nearly had to duck for that last image:)). The strain to eye-adjustment, however, is slightly more pronounced on images 3 and 4, so I would imagine that there might be a limit that one can push this filter to. But that said, we are looking at four images with increasing depth, so, perhaps, it is the changing from looking at one image to the next that is producing the additional eye-strain. A single image, perhaps, with maximum depth, may not be then noticiable?
Jay