Viewing stereo pictures on Sony Xperia Z5 Premium

I started this new thread in order to share my experience on the topic AND provide a place for constructive comments and other useful info.

The baseline: I'm addressing only stereo (stills) photography, not VR, video, etc.

Claim #1: the viewer for stereo pairs is historically called "stereoscope", and I don't see any reason to rename it into "VR glasses"

Claim #2: phones with less than 4K resolution are not suitable for viewing stereo photos at a reasonable resolution:

- 4K (3840x2160) is 8Mpix, thus up to 4MPix per an eye

- QuadHD (2560x1444) is 4Mpix, thus up to 2MPix per an eye

- the reasonable expectation is to come at least close to stereo slides; assuming the full slide is ~16 MPix and rectangular area is used for stereo, we get at least ~10 MPix per an eye

So, while 4K is still insufficient, anything less than it shouldn't even be considered.

Sorry the owners of those fashionable korean phones - only Sony Xperia Z5 Premium is more or less up to the task.

Now to my experience with modern stereoscopes: I saw no one that can cover the field of view of 5.7 inch screen with adequate quality.

Here is what I tried:

- Shinecon VR: great mechanics but the lenses are too bad at the border - absolutely unusable

- Leje mini VR: enormous geometric distortion; still cannot see the outer area properly

- Bobo VR Z4: better, but still the borders are too unsharp

- Homido V2: some improvement; if I add at least ~12% of black border to each side of the image, I can view it. Still 12% at each side gives 24% per a dimension; too much of resolution loss

- VR fold: simpler and cheaper than all the above, but actually much better. I can view the pictures after adding "only" ~7% of black border to each side. I do need to pick the viewpoint for each picture though; one cannot object the whole area from one point with good quality.

Hope this helps,

Oleg.