Reddit reviews Ajax Scientific Polished Glass Double-Convex (Bi-Convex) Lens, Spherical, 50 mm Diameter, 50 mm Focal Length
We found 2 Reddit comments about Ajax Scientific Polished Glass Double-Convex (Bi-Convex) Lens, Spherical, 50 mm Diameter, 50 mm Focal Length. Here are the top ones, ranked by their Reddit score.
Double-convex (bi-convex) lens for demonstrating optical principles and effects for studentsTwo outwardly curved surfaces converge light rays to a pointFocal length is 50mmLens is 50mm in diameterMade of polished glass with ground edges
The official cardboard lenses are 30mm biconvex lenses with a focal length of 45mm. If you cant see the edges of the screen (I cant) you could swap larger lenses with the same focal length to get a better field of view.
Maybe these would work? A cardboard shim might be needed since the focal length is 50mm.
http://www.amazon.com/gp/product/B00EPQ9SO4/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER
this would be better, you want a minimum of 34mm diameter. Longer focal length shows more of the screen.
http://www.amazon.com/Ajax-Scientific-Double-Convex-Bi-Convex-Spherical/dp/B00EPQ9SO4/ref=pd_sim_147_5?ie=UTF8&dpID=31fQ4P7mxYL&dpSrc=sims&preST=_AC_UL320_SR240%2C320_&refRID=0AQNKQJ6H2VY6X2S23W1