Anyone in the UK looking for Fresnel lenses might find this useful. CPC, a branch of the Farnell electronics giant sells various sizes of these babies :) sizes (mm), stock codes and prices are:- 400x360 AV03424 28.47 620x480 AV03425 53.14 750x550 AV03426 70.65 750x420 AV03427 69.05 840x470 AV04415 76.68 That last one is a massive 38" wide! Contact CPC on 08701-202530 Roy.