I've improved my PhotoFocus .
Now I can keep it ( at least at this day) while I turn over the page or blink the eyes.

My questions are ...
Is seeing the blip page = in the PhotoFocus state?

What's the difference between de-focusing and PhotoFocus as mentioned at P.44?

If I can see the blip page , do I need to notice the 4 corners?

Thanks for help.