Making a traditional glass lens requires a lot of experience, skill, and patience grinding a piece of glass to the required shape, and is not for the casual experimenter. Making a glass Fresnel ...

The process involves using lenses and mirrors to bounce the view up into the viewfinder ... trying different concave and Fresnel lenses plus a tiny square mirror he found at a craft store.

While not useful for cameras, the fresnel lens came around this time in 1818 ... built into the screens allowing for a wider field of view with less weight and bulk. The future certainly holds ...