Lens and flash

A lens for reducing a divergence of light of a light source comprising:

• a light entrance side having a plurality of Fresnel elements;
• a light exit side opposite the light entrance side, wherein the light exit side has a plurality of exit lenses having a second focal length;
• and
• an optical axis,
• wherein the Fresnel elements and the exit lenses are optically associated with one another in a one-to-one manner,
• wherein each Fresnel element has an entrance surface which is convex in shape and which forms an entrance lens having a first focal length,
• wherein each Fresnel element has a deflection surface arranged directly downstream of the entrance surface,
• wherein the deflection surface is configured to deflect the light which entered the lens through the entrance surface by total internal reflection towards an associated exit lens, and
• wherein, with a tolerance of at most 20% of the first and the second focal lengths, each entrance surface and the associated exit lens are located in the interrelated focal points.