Perfect fit for Google Cardboard lens (25 diameter / 50 focal length). You will find it on aliexpress.
Added (hardcoded) support material, you don't need to print with support material
Improved elastic holder
Pin mark to align with screen center
Elastic holder angle adjustment Tested with:
Nexus 4
Nexus 5
Xperia ZL
Galaxy S4
See Instructions!
Instructions
Printed with Prusa i3 Use:
PLA
NO support material
15% fill
Glue stick to avoid unstick from bed For lens holder:
At layer 5, (with layer width 0.3) pause printing and put the lens in hole (as seen in the photo).
Print the lens holder separately, because printer travel can damage the lens. I used this elastic buckle scaled in 0.6: http://www.thingiverse.com/thing:268143