Your telephoto lens could potentially save your life with this little trick

by Gannon Burgett

posted Sunday, August 16, 2015 at 12:27 PM EST

It might not be what you purchased your $2,000 70–200mm f/2.8 lens for, but in an emergency situation did you know can use your telephoto lens as a means to start a fire?

In The Modern Man’s Guide to Life, the authors note that in a pinch you could use your lens as a magnifying glass of sorts to focus sunlight onto a pile of tinder in hopes of starting a fire. Specifically the book notes:

In a pinch, a telephoto lens will also work to start a fire. Open the lens to the maximum aperture and focus a tiny spot of sunlight on dry tinder by holding the lens at the optimum distance for the concentration of the light. Be patient; this method can take fifteen or twenty minutes.

The likelihood of someone being stranded somewhere while simultaneously carrying around a telephoto lens is minimal, but it’s a neat and potentially life-saving tip in the event it does happen.

(via Deadspin)