Viewing stereo pairs on VR HMDs

3D Gunner - You are right, the stereo image of the Mushroom which I had a link to , has a spacing of 59mm and not 66mm ( as seen on my Sony Xperia Z5 premium phone ) as I had intended. However is does illustrate the small size and the separation of the left and right images to get a full image when view in a VR headset.

When I view the Mushroom image on on Sony Xperia Z5 premium phone which is placed in the  Zeiss VR ONE headset I find the mushroom does not have much a a 3d effect , but if I zoom in on the image slightly so that the spacing increases from 59mm to 66mm the 3d effect is greatly improved. If I zoom in a slight bit more so that the spacing is 68mm , I get a double image of the mushroom. It would appear that spacing of the left and right image needs to be between say 62mm and 67mm in my case. There is no mechanical adjustment on the Zeiss VR ONE headset for varying the spacing also no mechanical adjustment for focal length ( dioptre adjustment ).  I measured the distance between the centre of the two magnifier lens built in to the head set  to be 66.5mm. The distance between the magnifier lens and surface of the phone is about 40mm.

I installed the VR player ( for Android ) on my Sony Xperia Z5 phone and downloaded the 3 hi resolution images. The position tracking worked.  I was able to  zoom in on the hi resolution images , but if I zoomed too much so the spacing was 68mm or more I got a double image.