All about lenses. visit http://goes.flexinet.com.au/default.htm. compiled by Mr G July 2008. http://www.heussneroptics.com/Convex%20Lenses%20-%20Icon.jpg. Describe the shape of typical convex lenses. http://i.pbase.com/u40/tkt/large/40599248.LighthouseLamp.jpg. How are convex lenses used?. - PowerPoint PPT Presentation