Posted by: Anonymous
fresnel lense - 07/15/01 02:02 AM
A fresnel lens is a great back up fire lighting tool and it is only the size of a credit card, so it will take up less space in a survival kit. I have found it to work just as well as a magnifying glass. <br><br>
Posted by: oceanside
Re: fresnel lense - 01/19/08 12:51 PM
Found this version of the Fresnel
HERE "The Fresnel Lens Fire Starter is more commonly known as a credit card magnifier. However, our version has 4 power magnification, much more than the 2X or 3X of standard credit card magnifiers."
Posted by: Ian
Re: fresnel lense - 01/19/08 03:16 PM
It is not magnification that matters but area (size). The bigger the area the more energy captured and focussed on the ignition spot.
Try a Fresnel lens from an old overhead projector (plenty around). It will be about a foot square or more. No problems with ignition but a bit difficult to put in your pocket!
OHP Lens