Indeed; I've played around with various concentration methods (along with sun imaging using lenses). My US letter-sized Fresnel lens can easily start a tinder/

Indeed; I've played around with various concentration methods (along with sun imaging using lenses). My US letter-sized Fresnel lens can easily start a tinder/kindling fire in a few seconds, and I've managed to melt a lot of things accidentally jsut by pointing the lens at the sun for a few seconds when the solar filter was not installed.